Widal Test- Introduction, Principle, Procedure, Interpretation and Limitation 4.21/5 (875)

Widal Test- Introduction, Principle, Procedure, Interpretation and Limitation

Introduction of Widal Test

  • Widal Test is an agglutination test which detects the presence of serum agglutinins (H and O) in patients serum with typhoid and paratyphoid fever.
  • When facilities for culturing are not available, the Widal test is the reliable and can be of value in the diagnosis of typhoid fevers in endemic areas. 
  • It was developed by Georges Ferdinand Widal in 1896.
  • The patient’s serum is tested for O and H antibodies (agglutinins) against the following antigen suspensions (usually stained suspensions):
    S. Typhi 0 antigen suspension, 9, 12
    S. Typhi H antigen suspension, d
  • S. Paratyphi A 0 antigen suspension, 1, 2, 12
    S. Paratyphi A H antigen suspension, a
    S. Paratyphi B 0 antigen suspension, 1, 4, 5, 12
    S. Paratyphi B H antigen suspension, b, phase 1
    S. Paratyphi C 0 antigen suspension, 6, 7
    S. Paratyphi C H antigen suspension, c, phase 1
  • Salmonella antibody starts appearing in serum at the end of first week and rise sharply during the 3rd week of endemic fever. In acute typhoid fever, O agglutinins can usually be detected 6–8 days after the onset of fever and H agglutinins after 10–12 days.
  • It is preferable to test two specimens of sera at an interval of 7 to 10 days to demonstrate a rising antibody titre.
  • Salmonella antigen suspensions can be used as slide and tube techniques.

Principle of Widal Test

Bacterial suspension which carry antigen will agglutinate on exposure to antibodies to Salmonella organisms. Patients’ suffering from enteric fever would possess antibodies in their sera which can react and agglutinate serial doubling dilutions of killed, coloured Salmonella antigens in a agglutination test.

The main principle of widal test is that if homologous antibody is present in patients serum, it will react with respective antigen in the reagent and gives visible clumping on the test card and agglutination in the tube. The antigens used in the test are “H” and “O” antigens of Salmonella Typhi and “H” antigen of S. Paratyphi. The paratyphoid “O” antigen are not employed as they cross react with typhoid “O” antigen due to the sharing of factor 12. “O” antigen is a somatic antigen and “H” antigen is flagellar antigen. 

Preparation of Widal Antigens

  • H suspension of bacteria is prepared by adding 0.1 per cent formalin to a 24 hours broth culture or saline suspension of an agar culture.
  • For preparation of O suspensions of bacteria, the organisms is cultured on phenol agar (1:800) to inhibit flagella.
  • Standard smooth strains of the organism are used; S Typhi 901, O and H strains are employed for this purpose.
  • The growth is then emulsified in small volume of saline, mixed with 20 times its volume of alcohol, heated at 40° C to 50° C for 30 minutes and centrifuged.
  • The antigens are treated with chloroform (preservative) and appropriate dyes are added for easy identification of antigens.

Procedure of Widal Test


  1. Place one drop of positive control on one reaction circles of the slide.
  2. Pipette one drop of Isotonic saline on the next reaction cirlcle. (-ve Control).
  3. Pipette one drop of the patient serum tobe tested onto the remaining four reaction circles.
  4. Add one drop of Widal TEST antigen suspension ‘H’ to the first two reaction circles. (PC & NC).
  5. Add one drop each of ‘O’, ‘H’, ‘AH’ and ‘BH’ antigens to the remaining four reaction circles.
  6. Mix contents of each circle uniformly over the entire circle with separate mixing sticks.
  7. Rock the slide, gently back and forth and observe for agglutination macroscopically within one minute.


  1. Pipette one drop of isotonic saline into the first reaction circle and then place 5, 10, 20, 40, 80 ul of the test sample on the remaining circles.
  2. Add to each reaction circle, a drop of the antigen which showed agglutination with the test sample in the screening method.
  3. Using separate mixing sticks, mix the contents of each circle uniformly over the reaction circles.
  4. Rock the slide gently back and forth, observe for agglutination macroscopically within one minute.


In Widal Test, two types of tubes were originally used:
(1) Dreyer’s tube (narrow tube with conical bottom) for H agglutination and
(2) Felix tube (short round-bottomed tube) for O agglutination.

Now a days 3 x 0.5 ml Kahn tubes are used for both types of agglutination.

  1. Take 4 sets of 8 Kahn tubes/test tubes and label them 1 to 8 for O, H, AH and BH antibody detection.
  2. Pipette into the tube No.1 of all sets 1.9 ml of isotonic saline.
  3. To each of the remaining tubes (2 to 8) add 1.0 ml of isotonic saline.
  4. To the tube No.1 tube in each row add 0.1 ml of the serum sample to be tested and mix well.
  5. Transfer 1.0 ml of the diluted serum from tube no.1 to tube no.2 and mix well.
  6. Transfer 1.0 ml of the diluted sample from tube no.2 to tube no.3 and mix well. Continue this serial dilution till tube no.7 in each set.
  7. Discard 1.0 ml of the diluted serum from tube No.7 of each set.
  8. Tube No.8 in all the sets, serves as a saline control. Now the dilution of the serum sample achieved in each set is as follows: Tube No. : 1 2 3 4 5 6 7 8 (control) Dilutions 1:20 1:40 1:80 1:160 1:320 1:640 1:1280.
  9. To all the tubes (1 to 8) of each set add one drop of the respective WIDALTEST antigen suspension (O, H, AH and BH) from the reagent vials and mix well.
  10. Cover the tubes and incubate at 37° C overnight (approximately 18 hours).
  11. Dislodge the sedimented button gently and observe for agglutination.

Above protocols are obtained from WIDAL TEST: Swemed Diagnostics

Interpretation of Widal Test


Interpretation of Widal Test- Slide Method

  • Agglutination is a positive test result and if the positive reaction is observed with 20 ul of test sample, it indicates presence of clinically significant levels of the corresponding antibody in the patient serum.
  • No agglutination is a negative test result and indicates absence of clinically significant levels of the corresponding antibody in the patient serum.


Interpretation of Widal Test- Tube Method

  • The titre of the patient serum using Widal test antigen suspensions is the highest dilution of the serum sample that gives a visible agglutination.
  • The sample which shows the titre of 1:100 or more for O agglutinations and 1:200 or more for H agglutination should be considered as clinically significant (active infection). Example: In the above figure, titre is 160.
  • Demonstration of 4-fold rise between the two is diagnostic.
  • H agglutination is more reliable than O agglutinin.
  • Agglutinin starts appearing in serum by the end of 1st week with sharp rise in 2nd and 3rd week and the titre remains steady till 4th week after which it declines.

Limitations of Widal Test

  • The Widal test is time consuming (to find antibody titre) and often times when diagnosis is reached it is too late to start an antibiotic regimen.
  • The Widal test should be interpreted in the light of baseline titers in a healthy local population.
  • The Widal test may be falsely positive in patients who have had previous vaccination or infection with S. Typhi.
  • Besides cross-reactivity with other Salmonella species, the test cannot distinguish between a current infection and a previous infection or vaccination against typhoid.
  • Widal titers have also been reported in association with the dysgammaglobulinaemia of chronic active hepatitis and other autoimmune diseases.
  • False positive Widal test results are also known to occur in typhus, acute falciparum malaria
    (particularly in children), chronic liver disease associated with raised globulin levels and disorders such as rheumatoid arthritis, myelomatosis and nephrotic syndrome.
  • False negative results may be associated with early treatment, with “hidden organisms” in bone and joints, and with relapses of typhoid fever. Occasionally the infecting strains are poorly immunogenic.
  • False negative Widal tests may be due to antibody responses being blocked by early antimicrobial treatment or following a typhoid relapse.
  • Severe hypoproteinaemia may also prevent a rise in 0 and H antibody titres.
  • The antibody levels found in a healthy population however, may vary from time to time and in different areas, making it difficult to establish a cut off level of baseline antibody in a defined area and community.
  • In low typhoid endemic areas, weak and delayed O and H antibody responses limit the usefulness of the Widal test. Variations also exist between laboratories in the performance and reading of Widal tests which compromise further the reliability of the test.
  • The World Health Organization (WHO) has said that due to the various factors that can influence the results of a Widal test, it is best not to rely too much on this test.

Widal Test- Introduction, Principle, Procedure, Interpretation and Limitation

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Sagar Aryal

I am Sagar Aryal, a passionate Microbiologist and the Scientific Blogger. I did my Master's Degree in Medical Microbiology and currently working as a Lecturer at Department of Microbiology, St. Xavier's College, Kathmandu, Nepal. I am particularly interested in research related to Medical Microbiology and Virology. Find me on Facebook, Twitter or Linkedin !!!


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  1. dear/sir
    I sow same one patient widal test result
    Typhoid O=1:320
    Typhoid H=1:160
    he feeling hedage, and fever and stomach pain
    please tell me reporting results positive or negative

  2. I tested for a significant titre 1:80 is this positive or negative?

  3. What is the salmonella D anti-serum is ?
    Salmonella D anti-serum is used for the serotyping of:
    A) S.paratyphi A
    B)S.paratyphi B
    D) any of above

  4. Pls the result I got was. o -1/20 all thru while h-1/20,1/40,1/40,1/40, pls what’s the significant titre

    1. I m rashid…Sir i m felling fever after mild common cold..my widal report display
      S.Typhi H….. -ve
      S.Typhi o….. 1:40
      S.Typhi AH …-ve

      Should this parameters reflect my positiveness. Of Typhoid infection.

    2. The significant titer is 1:80 and above

  5. Negative.

  6. SALMONELLA TYPHI “O”_ 1:80 Dilutions
    SALMONELLA TYPHI “H”_ 1:80 Dilutions
    SALMONELLA TYPHI “AH”_ 1:20 Dilutions
    SALMONELLA TYPHI “BH”_ 1:20 Dilutions
    What is your opinior, is it negative or positive.

  7. Sir please is this widal test result significant. I was admitted in hospital and treatment for typhoid two weeks ago.
    Sal typhi O 1:160 H 1:160
    Sal paratphi A. O 1:80 H 1:80
    B. O 1:160 H 1:160
    C. O 1:80 H 1:160
    Thanks a lot

    1. Ojukwu Kenechukwu

      Its very significant and requires treatment. Ur titre values are up. You have five 160’s which is such a high titre. I do hope you feel better now based on the medication you are placed on?

  8. Sir, my wife age 35 her widal report is

    TO – 1:160
    TH – 1:160
    AH – 1:80
    BH – 1:80

    how this report Negetive or Positive?

  9. Musa Haliru Ahmad

    Btw O and H, which one is positive for widal?

    1. If O antigen is => 1:160 then it is positive . When H antigen is => 1:160, it means not positive but active infection.

  10. Hello sir..nice article. Why are we not detecting S.paratyphiC in widal test??because some kits contains antigen for S.paratyphiC, why not in others?

  11. Dear All,

    My 7 yrs kid’s WIDAL Test report are:

    S.TYPHI ‘O’ – 1:160
    S.TYPHI ‘H’ – 1:320
    S.TYPHI ‘A0’ – 1:40
    S.TYPHI ‘AH’ – 1:40
    S.TYPHI ‘BO’ – 1:40
    S.TYPHI ‘BH’ – 1:40

    He is having stomach pain, dizziness, feeling sleepy most of the time since last 8 days and fever of 102 and above since last 4 days.
    Since last 4 days, after ‘Ibuprofen’ fever syrup (300 mg) and ‘Cefixime’ antibiotic (400 mg/12 hours) application fever of 102 and above has been continuing every after 9/10 hours.

    We are so panic…. Please reply us with your advice.

    Is the having Typhoid or not?
    Is this stomach pain is due to typhoid or something else ?
    Which is the treatment procedure ?
    How many days it will may continue ?

  12. Dear Sir,

    My 7yr kid’s WIDAL Test report as per below;

    S.TYPHI ‘O’ – 1:160
    S.TYPHI ‘H’ – 1:320
    S.TYPHO ‘AO’ – 1:40
    S.TYPHI ‘AH’ – 1:40
    S.TYPHO ‘AO’ – 1:40
    S.TYPHI ‘BH’ – 1:40

    He is having some stomach pain, bhumiting since last 6 days and fever of 101/102 after 4/5 hours. After Paracitamol syrup and Cefixime 400 mg/12 hours antibiotic application no development found.

    We are so panic…

    Request your urgent help…..

    Is the having Typhoid or not?
    Is this stomach pain is due to typhoid or something else
    please advise the treatment process.

  13. Hello
    Test My Vidal
    OB1 / 40
    OD1 / 80
    The rest are negative headlines
    I am sick?

  14. Dear All,

    My 3yr old child’s WIDAL Test report as per below;

    S.TYPHI ‘O’ – agglutination seen 1:40 titre
    S.TYPHI ‘H’ – agglutination seen 1:40 titre
    S.TYPHI ‘AH’ – No agglutination seen
    S.TYPHI ‘BH’ – No agglutination seen

    He is having stomach pain, dizziness, feeling sleepy all time since last 17 days and fever of 102 and above since last 4 days and now after FLEXON fever syrup and ZIFI 100 antibiotic application since last 3 days body tem. Is normal but still having stomach pain & dry heavy coughing…..

    Blood report shown 3400 WBC against normal range of 4000 to 11000……and CRP quantitative 6.6 mg/L against normal range of <2.8

    One doctor said he is having typhoid fever and other said he is having viral fever…. he is on antibiotic – 7.5ml (ZIFI 100) since last 4 days…..along with FLEXON (10ml), Asthalin (3.5ml), Bro-zedex (3.5ml) and frisium table (2 per day) and cyclopean (5ml) when he is having acute stomach pain.

    We are so panic…..as he is having febrile convulsion in last Aug-2016, hence any fever above 100F makes us in tremendous panic and worry….

    Request your urgent help…..

    Is the having Typhoid or not?
    Is this stomach pain is due to typhoid or something else
    Is this dry heavy cough is due to typhoid or something else

    1. so appreciate.. For your collaboration model micro …..

  15. It’s a really nice article keep it up, procedures are spot on

  16. Dr Rajendra Khadke

    How many days widely will be positive after enteric fever

  17. S typhy o antigen 1:160
    Sir typhy H antigen 1:80
    S Para typhi Ah antigen 1:20

  18. Good day, I have suffered from s.typhi for 10 years ranging from 160-320. I am always in and out of the hospital and I have taken all antibiotics.please I need your advice because it’s affecting my life badly.

    1. Do a culture and then sensitivity. You may be on an antibiotic regime which is not effectively sensitive to the organism. Then once an effective antibiotic I’d prescribed make sure you are administering it as prescribed that is do not skip any until course is complete. And ensure to complete the cause even if you’re feeling better.
      Hope that suffices

    2. sir ,u have to take homoeopathic treatment for recurrent typhoid.

    3. dr Mohammad iqbal

      1-Repeat your test at medical college level. Go and discuss youe case to some Prof cum Dr of microbiology department. Request for test that takes 18 hrs to give result.
      2- Kindly do your urine and stool culture for salmonella if prof cum Dr suggests you.
      Now comes the treatment part…….
      Your and such type of other case are called Carrier of enteric fever. If otherwise no problem leave it other wise you may need removal of galk bladder

  19. i have been having typhoid for 10 years . Been on all antibiotics but s.typhi still remains between 160-320. I really don’t know what to do anymore. Please advice me as I am always in and out of the hospital. Thank you

    1. Being on Antibiotics for that long is not the solution and not the best idea either considering that drugs are xenobiotics and again, you could eventually become resistant to most of the antibiotics. However, the best approach could be to run a stool MCS (Microscopy, Culture and Sensitivity). Through this Microbiological procedure, you could actually know the right antibiotic to take and at what amount and dosage and what period it would need to clear your typhoid.

      Finally, ensure to complete the dosage as prescribed because when you don’t complete your treatment regime for microbial infections, they tend to reoccur and when it does, they must have grown quite resistant to the first drug you use.

      You may also have to mind your source of drinking water. Live Healthy.

  20. What is positive control and negative control

  21. Hi , could someone please advise he meaning of hear test results? ;
    Salmonella paratyphi BH Ab 1280
    “. “. AO Ab 20
    “. “. AH ab <20
    ". ". BO ab 20

  22. Sir please tel me the report of mine whether widal test is positive or negative
    O antigen 1:160
    H antigen. 1:80

  23. .y widal test for
    s typhi:o 1:20

  24. Hello sir i want to know my report
    S.typhi o. Possitive up to 1:160
    S.typhi o. Possitive up to 1:80
    It mns i have typhoid or not

  25. Hi my brother had fever and took test on two diff dates. His result is
    Jan 21
    salmonella thypi “o” – positive 1:40
    Salmonella thypi “h” – positive 1:40
    Salmonella para thypi “ah” – negative
    Salmonella para thypi “bh” – negative

    1. Sir my wife widal test is
      Salmonella thphi O possitive 1:40
      H possitive 1:40
      Paratyphi A possitive 1:160
      B negative

  26. Hi All,
    I had typhoid from past one month, taken treatment (5 days Through IV and 1 week through Tablets), 20 days later i given for test, the report shows like this:

    S.TYPHI ‘O’ 1:80

    Can you please help me, Its Positive OR Negative.
    From past two days i have leg pain and body pain with fatigue.

  27. I am 69 years old.My widal test report is below

    1:30. 1:60. 1:120. 1:240.

    TO. – – – –
    TH. – – – –
    AH. – – – –
    BH. – – – –

    Please let me know the results.

    1. Positive or negative?

  28. my child (10 Years) report is below pls advise. this report is positive ?

    S.Typhi “O” Antigen : 1:120
    S.Typhi “H” Antigen : 1:120
    S.Paratyphi “AH” Antigen : TITRE<1:30 (NEGATIVE)
    S.Paratyphi "BH" Antigen : TITRE<1:30 (NEGATIVE)

  29. Hi. Is this report normal or positive?
    typhi (O) 1/40
    typhi (H) neg.

    1. akhlesh Kumar sharma

      o-1:40 & H:40 then Positive or negative Thypod

  30. S.TYPHI (O) 1:32 TITRE
    S.TYPHI (H) 1:80 TITRE



    1. My Widal Test Report ::

      TO :- 1:80
      TH :- 1:160
      AH :- 1:40
      BH :- 1:40

  31. Ques …Without O or H positive only AH or BH can be positive .. In widal

  32. hi sir
    this is my widal test report by the slide method. is I normal or not ?? . please help me
    1/20. 1/40. 1/80. 1/160. 1/320
    TYPHY ” O. –
    TYPHI ” H. – –
    TYPHI ” AH. – – –
    TYPHI “BH. – – –

    1. 1:160and another is 1:160

  33. hi sir
    this is my widal test report by the slide method. is I normal or not ?? . please help me

  34. Sir,
    Kindly tell me about this report, wether it is positive or negative.
    S.Typhi “O” (Somatic) Antigen Titre <40
    S. Typhi "H" (Flagellar) Antigen Titre <40
    S.Paratyphi A "H"(Flagellar)Antigen Titre <40
    S.Paratyphi B "H" (Flagellar)Antigen Titre <40

    1. dr. vishal gupta pathologist

      You’re report is normal.

    2. Insignificant RXN Titre value


  35. which part of the body is O and h found

  36. Hello Sir, please can syphilis be treated to get out completely from your blood stream?

  37. S. Typhi h 1:640
    S. Typhi o 1:80
    S. Typhi ah 1:40
    S. Typhi bh 1:20
    Is this good

    Plzz rply

  38. Hello sir pls I v been experiencing headache and decided to test for malaria and typhoid . Malaria came out negative. Typhoid came with typhi o 1/160 and H 1/20. Am confused.pls explain to me .is it deadly serious or it will changed to negative when I take antibiotics.pls prescribe one for me.thank u.

  39. sir plz help me my Typhoi O is 1:40 and H is 1:40…Is it normal or not!what should i do?

  40. sir Widal test normal value

  41. Of IgM and IgG, which one shows the past infection; and wik shows active infection?

  42. | 1:20 | 1:40 | 1:80 | 1:60 | 1:320 |
    TO > + + + – – |
    TH > + + + – – |
    AH > – – – – – |
    BH > – – – – – |

  43. Hi my wife report below i took review for 2 dr one says take typhoid medicine and other says it not relaible on second day if fever as she also has maleria check for typhoid after 2 days below is the report
    Typhi h 1/40
    Typhi O 1/160

    I am confused pls help

    1. Hi my wife report below i took review for 2 dr one says take typhoid medicine and other says it not relaible on second day if fever as she also has maleria check for typhoid after 2 days below is the report
      Typhi h 1/80
      Typhi O 1/160

      I am confused pls help

  44. Sir, My widal test positive came by card method & I have take 10 days heavy antibiotic.
    But after 10 day I have rechecked by slive method but surprisingly its came negative.

    Please explain its possible

  45. Sir, what is this result I have not understand this report. And I have not understand in English language please tell us in Kannada language. My Blood Report is this type
    salmonella ‘O’ 1:320
    salmonella ‘H’ 1:160
    Salmonella ‘AH’ 1:40
    Salmonella ‘BH’ 1:20

    1. Ur lab report says ur Widal test is positive for typhoid fever consult physician as soon as possible

  46. S. Paratyphi A(H) Antigen Present (1:80)

  47. A. Paratyphi A(H) Antigen PRESENT (1:80)

  48. My Widal test report is O-1:320, H-1:80, AH-1:80, BH-1:80
    Plz explain my report. Is that serious problem?

  49. widal test 1:20 1:40 1:60 1:80 1:160 1:320
    s typhi’o’ + + + + +
    s typhi’h’ + + + – –
    s paratyphi AH + – – – –
    s paratyphi BH – – – – –

  50. Hi,
    what does this result mean?

    TO : 1/320
    TH : 1/160

    Thank you in advance



  51. my report is
    Antigen O 1:160
    Antigen H 1:320
    is it normal or possitive



    2. its a positive report

  52. Hi,

    Could you please look into the report below and advice me, Is my health condition disturbed or am I normal?

    S Typhi ‘H’ Titre 1/40
    S Typhi ‘O’ Titre 1/80
    S Para Typhi ‘A’ Titre 1/20
    S Para Typhi ‘B’ Titre 1/20

    Kindly let me know at the earliest



  53. ANC
    O:1:20,1:40,1:80, 1:160+
    Paratyphi AH 1:20,1:40+
    Paratyphi BH 1:20+

  54. Salmonella typhi O 1:80 dilutions
    Salmonella typhi H. 1:80 dilutions
    Salmonella paratyphi AH 1:20 dilutions
    Salmonella paratyphi Bh. 1:20 dilutions
    Impression Positive +ve need to know the results of this is this normal or high typhoid

  55. kaushlesh singh gurjar

    My report is
    O _ 1:160
    H _ 1:320
    Ah neg.
    Bh neg.

    Please tell me my health condition. And how many days remove typifaiod

    1. My report is
      O _ 1:160
      H _ 1:320
      Ah neg.
      Bh neg.



  56. hello sir it is very difficult to learn total microbiology notes and questions please tell me how to learn easy method its very confusing sir

  57. The following is my widal Test Report.
    S.Typhi Antigen O :<1 in 20 dilutions
    S.Typhi Antigen H :<1 in 20 dilutions
    S.Paratyphi A :<1 in 20 dilutions
    S.Paratyphi B :<1 in 20 dilution

    What does this report mean? positve or nagative?

  58. I have the following result
    S.TyphiAntigen O :<1 in 20 dilutions
    S.TyphiAntigen H :<1 in 20 dilutions
    S.Paratyphi A. :<1 in 20 dilutions
    S.Paratypi B. :<1 in 20 dilutions
    Whether I am Typhoid positive or negative?

  59. Yahaya Abubakar Aya

    so lovely

  60. My condition is

    S typhi O negative
    S typhi H negative
    S paratyphi AH 1/160
    S paratyphi BH 1/160
    I have slight fever in morning hours, but return to normal during day time.
    Is it due to my previous infection with S typhi O positive, or is it new infection?
    Please interpret.
    Thanks very much for helping me in advance.

  61. S.Paratyphi B – O antigen Negative
    – H antigen POSITIVE Titre = 80
    What does this mean?

  62. Useful Guide.
    Please explain.
    Salmonella typhi “O”Titre :1:80 Dilutions ?
    Salmonella typhi “H”Titre :1:80 Dilutions ?
    Please reply.

  63. Hello
    My test results after taking antibiotics “cipro tabs” for 10 daysis still:

    TYPHI TO. Titre 80
    PARATYPHI BO. Titre 160

    Please what should i do and what should i take?

  64. Titre result shows
    SO&SH +VE for 1:20 what does it mean

  65. Widal test report:

    1:20 1:40 1:80 1:160 1:320 1:640 1:1280
    O + + + + + + +
    TH + + + + + + –
    AH – – – – – – –
    BH – – – – – – –

    Something wrong with the report? This is report of my mother who is 51 years old.
    Please comment

    1. 1)the titration method is wrong.2)contaminated sample or reagent.



  66. Here is my blood examination report

    “o” antigen agglutination 1:80 Dilution
    “H” Antigen Agglutination 1:160 Dilution
    Para A(H)Antigen Agglutination 1:20 Dilution
    Para B(H)Antigen Agglutination 1:20 Dilution

    Serum Bilirubin 0.8 Mg%

    can pls check this report

    1. To +1/60, th +1/60, ah -1/60 , bh – 1/60
      To – 1/120,th – 1/120,ah – 1/120,bh-1/120
      To – 1/240,th – 1/240,ah – 1/240,bh-1/240
      I know about typhoid positive or negative

  67. My widal test reports are:
    S.typhi O= less than 1:160
    S.typhi H=less than 1:80
    S.para typhi AH: negative
    S.para typhi BH: Negative
    Is it normal or I still have the fever??? And does it transmit to other person through sex??

    1. Vikram, 1:80 normal. But

      1:120 above typhoid positive.

  68. Agglutination jyada or kam how to difine titre ratio.

  69. Pls help me in knowing the general tube method and dilution for this test

  70. Dr Ramesh Wadhwani

    As per my knowledge O antigen is important than H

    1. Yes you are right but H antigen is important as well as it denotes the past infection

    s.typhi ‘o’ & ‘H’ (How much pt.serum (ul)taken and how much reagents add give the dilution details for given belw all dilutions

    1. 100 ul diluted serum + 20 ul reagent.

    2. Diluted serum 100ul+20ul reagent.

  72. idrees yusuf jabo

    thank you very much, this article helped in saving my behind

  73. hi my Widal report O-1:160. H-1:20 AH:1:20 BH:1:20 plz tel me this report or positive

  74. This is very important….,,,

  75. My Mother report
    O typhe….1/80

    H typhe….1/80

  76. please tell me about my report

  77. my widal report.
    o antisen : positive (1:40)
    H angigen : negative
    AH antigen : negative
    BH antigen : negative
    please tell me this report is negative or positive

    1. Negative

  78. My Mother widal test report.
    O typhe…..1/80
    H typhe. …1/80

    1. Widal test is negative

  79. My Mother widal test
    O typhe….1/80
    H typhe. 1/80
    Negative or positive

  80. My friend has Jaundice and the following test is also taken for him.

    Widal Test :

    Investigation Result

    S. Typhi ‘O’ Antigen 1 : 20 dils
    S. Typhi ‘H” Antigen 1 : 20 dils
    S. Para Typhi ‘AH’ Antigen 1 : 20 dils
    S. Para Typhi ‘BH’ Antigen 1 : 20 dils

    What does it mean?
    If something is not well, what precautions have to be taken?

    Please let me know in detail as we all stay far from home and need to take proper care of ourselves.

    1. Perfectly normal report. Typhoid do causes hepatitis leading to yellowish discoloration of eye but that is not a common presentation.

    2. My widal test for typhoid shows the following results. Tell me whether the report is negative or positive.
      Widal Report:
      S. TYPHI O 1:20
      s. TYPHI H 1:20
      S.PARATYPHI AH 1:20
      S.PARATYPHI BH 1:20

  81. Christine

    Please help me and interpret my widal test result below:

    20/40: 40/80: 80/160 ; 20/20


  82. why we use saline u this test can u tell me the reason?

  83. Pls am here to study I need your help about widal test.well done and good lecture

  84. My mummy widal test results is O,H,AH,BH, all Four is positive in 1:80.kindly suggest.

  85. Pradyot Prakash

    Go through the article on typhoid fever in which widal test was evaluated considering Nested PCR as Gold standard.

    1: Prakash P, Mishra OP, Singh AK, Gulati AK, Nath G. Evaluation of nested PCR in
    diagnosis of typhoid fever. J Clin Microbiol. 2005 Jan;43(1):431-2.


    Dr. Pradyot

  86. olakojo adeyemi

    For the past ten years i noticed that my widal test used to be highly reactive i.e btw 1:160 and 1:320 even after treating with ceftriazone… I want to know whether its possible to be a carrier.

  87. My test result is as follows
    S.typhi O 1/160; H 1/60; AO 1/120; AH 1/80; BO 1/160; BH 1/80; CO 1/120; CH 1/120
    Pls interpret.

  88. O-160. H-160. AH-40. BH-40 POSITIVE OR NAGITIVE

    1. The test says s typhil TO-Negative..S typhil TH titre160 positive. And S paratyphil AH.Negative S paratyphil BH.Negative. S typhil AO.negative.. S paratyphil BO.negative. Sparatyphil CO.negative. S paratyphil.CH.negative and malaria negaive. I feel terrible headache and weak

  89. my widal test is TO 1:160, TH 1:320, AH 1:40, BH 1:40,

  90. 1;320/1;160/1.160/1.160/1.60

  91. hi,my report is
    to ——
    th ——
    ah 1:40
    BH 1:160
    is it negative or positive

    1. Sir,
      I have typhoid nd report shows

  92. what is patient’s serum in widal test . r u taking blood or sputum for the test

    1. tahira nor@gmail.com

      only blood is uesd for widal test to check the reaction between ag and ab

    2. blood is centrifuged in a centrifuge at 3000rpm…and u must take the upper part of it…that is serum

  93. My widal test result is follows;

    S typhi TO 1:80
    S Paratyphi AO 1:40
    S Paratyphi BO 1:20
    S typhi TH 1:60
    S Paratyphi AH 1:40
    S Paratyphi BH 1:20

    Please let me know my fever condition…waiting for your response

    1. My report sayed that (Titee of > 1:80 is considered significant)

  94. For titre from 80 and above is considered significant (+)160(++) and so on,when using slide method, in this case pefloxacin tab 500mg to be taken one twice daily is advice to destroy the cell wall of the salmonella spp.

  95. Good day,

    Please kindly help out with this.

    O H
    S.typhi 1/40 1/80
    S.para typhi A 1/80 1/20
    S.para typhi B 1/20 1/20
    S.para typhi C 1/80 1/20

    Please kindly help me interpret it and also the correct medication for me to take and how serious it is.thank you

  96. Will rheumatoid arthritis problem show thypi h and o as positive. Please give your suggestions. In my mother’s report h and o is 1:80 and shown as positive.
    Is there and intrlink for both…

  97. Will rheumatoid arthritis problem show thypi h and o as positive

  98. Please my widal test was O – and H + with 1/80. Please am I positive and how serious is this results.

  99. Good day,

    Please kindly help out with this.

    O H
    S.typhi 1/40 1/80
    S.para typhi A 1/80 1/20
    S.para typhi B 1/20 1/20
    S.para typhi C 1/80 1/20

    Please kindly help me interpret it and also the correct medication for me to take and how serious it is.thank you

  100. widely test had been my result is
    Please say me negative or positive.
    But I don’t have fever only stomach pain and infection.

    How many days it take to cure,

    1. you are positive..but if you take treatment for 2 weeks daily..the disease will stop spreading and you will be surely healed..take care

  101. Hi, my Widal Test give me this results

    1:20 1:40 1:80 1:160 1:320
    A + + + + –
    B – – – – –
    H – – – – –
    O – – – – –

    Thanks for your help.

  102. I am studying the duration the antigens of Salmonella Typhi will remain in the blood and show a reactive result in a titre od 1:80. Could you please specify the duration of approximate days or months after febrile infection.

    Thanks in advance.

  103. Usama Dalhatu Abubakar

    Thank You Very Much May God Bless You

  104. What does that supposed to mean! Not significant ?! Could u please interprete
    BO 1:160 not significant
    TO 1:80
    Thank you anyway 🙂

  105. this website i appreciate how everything is systematically and well organized to clearly that every one follow easily i am saying thank you for your effort and simplifying to all procedures

  106. Please kindly interprete this for me. S.typhyi O 1/60
    S.typhyi H 1/20
    S.para typhyi AO 1/20
    S.para typhi BO 1/80
    S.para typhi BH 1/20
    S.para typi CO 1/20
    S.para typhi CH 1/20
    Please kindly help me interpretate it and also the correct medication for me to take and how serious it is.thank you

  107. i found H ANTIGEN TITRE 1:320


  108. Abubacker Siddique O M

    Pls say whether the report is positive or negative ?
    S.Typhi.O.S 1:60
    Typhi 1:60
    Para A 1:20
    Para B 1:20

  109. S.typhi O: 1/20
    S.typhi H:1/20
    is it positive or negative?

  110. what does this mean s.paratyphi AO , BO, BH, CO, CH, O, H….
    also what does the figure 1:40, 1:160 mean

  111. STO(Agglutination)less than 1:20
    STH(Agglutination)less than 1:20
    SPAH(Agglutination)less than 1:20
    SPBH(Agglutination)less than 1:20

  112. O 1:40,1:80&H 1:40

  113. TO=1/160 +ve TH=1/20 +ve
    TAH=negative TBH=negative

    Positive or negative?

    1. Positive for H

      1. Positive for O

      2. To 1:320
        TH 1:40

        my report positive or nagetive

  114. TO=1/160 +ve TH=1/20 +ve

    Positive or negative?

  115. Pls interpret this Widal test results. is it positive or negative?
    S typhil O =1:80 , H =1:80
    S.paratyphi A- O =1:20, A-H= 1:20
    “. ”
    A-O, C-O , B-H, C-H , all are 1:20


  116. Good work… continue educating

  117. wow ur article is very interesting nd useful especially to mii becoz am a medical lab scientis..go ahead sagar.

  118. Between. O and o which one is positive. Among the two?

  119. That is good continue investigate

  120. very interested

  121. nice one I will like to join

  122. my S Typhi O 1/80. s typhi BO 1/20. is this positive or negative ?

  123. My s typhi o is 1/80. My s typhi BO is 1/20. is this positive or negative result

  124. Very Very Helpful And Intresting Keep it Up Thanks

    1. Ah, i see. Well tha’ts not too tricky at all!”

    2. Hello sir
      My widal report is

      O 1:160
      TH 1:80
      A H 1:40
      B H 1:40

      is this is positive or negative ??

  125. Nice one keep it up.

  126. very informative and useful for my lab report. i’m 19 and currently in my 3rd year in the uni and hopefully microbiology will become my life.

  127. Zahid Eidaky Dawar

    Very information

  128. Can we didferentiate the Widal test positivity that is due to previous vaccination (or past infection) and due to recent infection ? Is there any guidelines to differentiate positivity depends on dilution? Or we have to depends on other investigation for this purpose ?

    1. can go for blood culture. only the live organisms shows growth.

  129. On ma way… l like it

  130. Thanks for the good work on widal test . I enjoyed reading it. But please I would like to know more on the interpretation and clinical correlation.

    1. Good work in the diagnosis of typhoid fever

  131. I’m a lab
    I happy to learn from here

  132. why is unheated serum use in widal test? please answer

  133. serum dilution
    1:30. 1:60. 1:120. 1:240
    s.typhi ‘ o’ . . .
    s.typhi. ‘h’. . . .
    is this means positive or negative

    1. Nothing like that bt
      1:20.1:40.1:80.1:160.1:320 and
      The significant titre is greater than or equal to 1:80 ie positive from 1:80 and above

  134. my
    to 1180
    th. 1180
    ah. 1140
    bh. 1140

  135. If reading is 1/160, then after ten days became 1/320 does this indicate an increase or a decrease? Kindly reply, what does this ratio mean 1 of what to 160 of what? Thanks a lot…

  136. My widal test is

    Typhi O 1/160 is +
    Typhi H 1/160 is +

    What is this

    1. My widal test is Typhi O 1/160 is + and Typhi H 1/160 is +

    2. Positve mixed infection

  137. I am a medical student and I like laboratory service in my lab……..!!!!!

  138. my typhi O is 1:80 and H is 1:80 is this is negative or positvie

    1. Negative

  139. Please kindly interpret – widal 20/80, 20/20, 20/20, 40/40

    1. there is nothing like that

  140. Day 1
    S.Typhi H Positive 1:160
    S.Typhi O Positive 1:160

    Day 25
    S.Typhi H Positive 1:320
    S.Typhi O Positive 1:320

    No ova & parasites observed
    Salmonella, shigella, E coli not isolated

  141. please interpret the following report
    s.typhi ‘o’ 1/20 1/40 1/80
    s.typhi ‘H’ 1/20 1/40 1/80 1/60

    1. Positive bt nothing like 1:60

  142. diagnosis is the mother of health solution

  143. My Widal Test is. O. 1/20. 1/20. 1/20. 1/20. H. 1/20. 1/160 1/20. 1/80. Sir am I positive or negative

    1. Mohammed Abdulkarim.


  144. Thnx for your SOP

  145. Continue more research,stoped using widal test due to many false post-RDTs for salmonella is my best

  146. Absolutely very useful!!

  147. Sir my widal test report is

    S.typhi “o” 1:160 dilu
    S.typhi “h” 1:160 dilu
    S.paratyphi “ah” : Negative
    S.paratyphi “bh” : negative
    it means

    1. Dag nabbit good stuff you whaepprsnippers!

  148. Heoll
    I am Chandrasekhar
    I did WIDAL test, test results mentioned below
    SALMONELLA TYPHI “O” >1:160 Dilutions
    SALMONELLA TYPHI “H” > 1:80 But No agglutination in 1:160 Dilutions
    What is opinion, it is either positive or negative…..

  149. I am a meadical student and i am intrastet in daignosis

  150. learning information, for interpretation if only H titre more than 1:120 is present with negative o than it would be considered as positive or negative,kindly highlight.

  151. 1) Salmonella typh O Titr : 1 in 40 dilution
    2) Salmonella typh H Titr : 1 in 40 dilution

    3) salmonella paratyph AH titr : less than 1 in 20 dilution
    4) salmonella paratyph BH titr : less than 1 in 20 dilution

  152. This is very interesting as it touches everything about widal test

  153. Widal result-20,,40,,80,,160,,320

  154. my widal test result
    salm. typl 1<40 1<40
    salm. paratypl. A 1<80 1<80
    Paratyphl.B 1<80 1<40
    PARATYPHL. C 1<80 1<40

    PLS can you exmplian

  155. good work sagar your article is very useful keep up the good work

  156. I like your website interesting and learned so much how to subscribe?

    1. Wonderful exaanlption of facts available here.

  157. pooja singh baghel

    hey Mr.sager aryal….ur article very use full for me…
    as a Bhms student I HV got to easy way to understand this method…thankuuu…may I join u???

  158. Your publication is good. Can I subscribe to it?

  159. i will join

  160. My widal test are as below:-
    SALMONELLA TYPHI “O”_ 1:80 Dilutions
    SALMONELLA TYPHI “H”_ 1:40 Dilutions
    SALMONELLA TYPHI “AH”_ 1:20 Dilutions
    SALMONELLA TYPHI “BH”_ 1:20 Dilutions
    What is your opinior, is it negative or positive.

    1. its negative.. its possitive only on 1:160 or above titre

  161. say’s thanks to Mr.sagar aryal

  162. Thanks… your article is very clear and useful to understanding microbiology..

  163. Article very well presented .. so helpfull>> thanks.

    1. Wow! Talk about a posting knkiocng my socks off!

  164. Well done Sagar Aryal for nice and short clear of different procedures
    This can help us tO follow as SOP guideline.you are a real Microbiologist.

  165. En Hockenheimring el turismo de McCarthy es descalificado por
    no pasar por el test de peso y Moreno no precalifica.

  166. Job well done. Thanks for this info.

  167. good job

  168. conaira dimasangca


  169. Very..useful..thanq Sagar Aryal..bro

  170. Its help to read during exams…

  171. kipkemoi Josphat

    I like your publish .you make me to be great microbiologist day by day.Thanks alot

  172. very interesting website I like it.

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