Enteric fever – Part 3 – Typhoid / Enteric fever Diagnosis, Widal test, Its Procedure and Interpretation

Sample
- It is done on the serum of the patient.
- A random sample can be taken.
Purpose of the test (Indication)
- This test is done to diagnose enteric fever (Typhoid and paratyphoid fever).
pathophysiology
- History of widal test:
- In 1896 widal test was discovered by George-Fernand Widal for the diagnosis of enteric fever.
- Enteric fever includes typhoid and paratyphoid fever.
- Paratyphoid fever is milder than typhoid fever.
- Enteric fever is also called typhoid fever.
- Typhoid fever is caused by the bacterium Salmonella Typhi.
- Salmonella typhi has an incubation period of 14 to 21 days. Sometimes may even longer.
- 30% of the cases become chronic carriers due to persistent infection of the gallbladder.
- This has flagellar antigen H antigen, and Lipopolysaccharides antigen is somatic or O antigen.
- The incubation period is 7 to 14 days.
- Typhoid fever is common in the developing world, where it affects about 21.5 million persons each year.
- Salmonella Typhi lives in humans and is also found in chickens and eggs.
- It is present in the blood and intestinal tract.
- The carrier can harbor bacilli in the gallbladder.
- Both patients and carriers shed Salmonella Typhi in their feces (stool).
Mode of spread
- Food: if food or drinks are contaminated.
- Spread from the carrier, who is shedding Salmonella Typhi.
- Contaminated drinking water: If sewage water is contaminated with Salmonella Typhi.
- Typhoid fever is more common in areas of the world where handwashing is less frequent.
- Once Salmonella Typhi bacteria are eaten or drunk, they multiply and spread into the bloodstream.
Signs and symptoms
- The patient has a fever, and the pattern of the fever is typical.
- Fever is persistent and does not touch normally. This may be as high as 103 to 104 F.
- The patient may feel weak.
- May have stomach pains, headaches, or loss of appetite.
- In some cases, patients have a rash of flat type and rose-colored spots.
The procedure of the Widal test:
- Serial dilution of the patient serum is taken 1:40 to 1:320
- Now add an equal volume of Salmonella antigen.
- This can be done as a Slide method or as a Tube method.
- When running in the tube, then incubate tubes for 12 hours or overnight.
- Prepare the serial dilution, as shown in the diagram.
Widal test procedure:
It is done as follows and can read the result where there is the start of the agglutination, as shown in the following diagram.
Drawback: This test will be positive after 7 to 10 days of Enteric fever.
- Serologically salmonella has 5 serogroups: A, B, C, D, and E based on O somatic antigen.
- Based on H-antigen are 1200 serotypes.
- 7 to 10 days antibody to D-somatic antigen appears.
- These antibodies against O antigens reach their peak by 3 to 5 weeks.
- H-flagellar antibodies appear later on.
- 7 to 10 days antibody to D-somatic antigen appears.
- Widal test will be positive after 7 to 10 days of infection.
- The titer of O-antibodies 1:80 is suspicious in unvaccinated patients.
- The titer of 1:160 is strongly suggestive of infection in unvaccinated individuals.
- The titer of 1:40 for Antibody to flagellar-antigen (H) are suspicious in unvaccinated individual.
- While 1:160 is strongly suggestive.
- Titers are much higher in the vaccinated individual.
- Vi antigen for S.typhi is used to screen the carrier. antibodies to Vi-antigen are positive in
- Based on H-antigen are 1200 serotypes.
Reading of the test
- The highest dilution of the serum is noted where there is agglutination.
- If it ends at 1:320, then that is the titer.
- The Widal test is positive
- if “O” antigen titer is
>1:160 = active infection.
- If the “H” antigen titer is
>1:160, it indicates past infection or in immunized persons.
- A fourfold increase in the titer (e.g., from 1:40 to 1:160) is diagnostic.
- if “O” antigen titer is
O antigen
- In the acute stage, Antigen O will be positive, and titer will be more than 1:160.
- O antigen appears early and also disappear early.
H antigen
- H antigen rises late and disappears late.
- This will be positive in the recovery stage.
Vi antigen
- This is an indicator of the carrier stage.
The false-positive test may be seen due to cross-reacting infections, including malaria.
Other diagnostic tests for the diagnosis of Typhoid (Enteric) fever are:
- Blood culture, which will be positive in the first week when the Widal test is negative.
- Stool culture.
- 60 to 70% of cases are negative during the first week, and more cases positive in the third week of infection.
- Stool 90% of the cases are cleared of the bacteria by the 8th week of infection.
- Urine culture.
- Bone marrow culture. This is a very sensitive test.
- Bone marrow 90% of the cases are positive despite antibiotic therapy if these are ≤5 days.
- Another serological test is Typhidot.
- The gold standard is the blood culture, where 90% of cases are positive in the first week.
- 50% of cases are positive by the third week.
- For better yield, centrifuge the blood and take a buffy coat for culture.
- Other samples are stool, urine, Rose spot, bone marrow, and gastric or intestinal secretions.
- When culture is done simultaneously on blood, bone marrow, and intestinal secretions, positivity is >90%.
- A small % become the carrier, and their stool culture remains positive for at least one year.
Culture in Enteric fever patients from a different site:
Time period | Clinical S/S | Blood | Stool | Urine | Bone marrow |
During I.P 0 to 1 week | diarrhea or constipation | negative | ± | negative | negative |
1 to 2 weeks | fever, headache, myalgia, cough | 80 to 90% positive | negative | negative | negative |
2 to 4 weeks | systemic toxemia | 80 to 90% positive | 80% positive | 25% positive | 90% positive |
4 to 5 weeks | recovering | negative except in complications | 50% positive | 10% positive | ± |
>5 weeks | Cholecystitis, osteomyelitis | negative except in complications | ± | ± | negative |
Treatment
- The drug of choice is chloramphenicol, but it has many side-effects.
- Ciprofloxacin is now a drug of choice.
- Ampicillin, amoxicillin, 3rd generation cephalosporins, and fluoroquinolones can be used.
- C0-trimoxazole is better than chloramphenicol with less side-effect.
Carriers:
-
- It is difficult to treat carriers because of gall bladder involvement.
- Ampicillin is the most useful drug, but it is to be given in larger doses and for a longer period of time.
- Chloramphenicol is less effective than ampicillin.
- Ciprofloxacin can also be tried.
- The ultimate end is cholecystectomy.
For Nonmedical (non-specialists) person explanation of Widal test (Enteric fever):
- Please advise the Widal test if the fever persists for more than 5 days and is constant. It does not touch the normal level.
- The titer of O antigen 1:40 is considered negative.
- Just see the O antigen titer if it is 1:160, indicate Enteric fever.
- If the O antigen is 1:80, repeat the test after 5 to 7 days, and now if the titer is 1:160, the rising titer again indicates acute infection.
- While H antigen does not indicate acute infection or acute enteric fever.
Good write up.
Thanks
Thanks a lot.
Widal test is explained in a very simple way.
Thanks.
What does it mean if someone has a 1:160
If it is O 1:160 means positive and you can repeat after 3 to 7 days, and you will find a rising titer.
Hello sir ..my widal test s typho o 1:320 and fever comes in my inside body 2 month normal fever ..
Dear
Your widal is positive. You need to take a course on antibiots.
Prof.Riaz
Dear
Your widal is positive. You need to take a course on antibiotics.
Prof.Riaz
Very well explainaton… Very useful
Thanks.
Thanks a lot
Sir, i have 1:320 in thypoid result
And i took injection course for 3 days morning and evening …. 10 days pills paracetamol and antibiotic… Still i am having severe headache sir…
1:320 if it is O antigen, then definitely it is enteric fever. These antibodies will disappear after a minimum of one year. First O antigen will disappear and later on H antigen.
Very well explained…
Thanks.
I appreciate your write-up, as it’s has ease enlightened me on my test results.
T
thanks
Widal test done on 9/09/20 give S typhi titre 1:180 after 20 days repeat test shows O titer negative (Nil)
How fast O titre disappears.
Please explain
O antigen titer negative means no typhoid fever. But titer of 1:180 was indicative typhoid fever but when there is no rising titer then typhoid fever possibility is out.
Please let me know about the H antigen titer. Your results are Confusing because O antigen toter can not become 0 in just 20 days.
Please reply earliest possible.
Replied to your question.
If widal- O 1:160 and H 1:80
And after around 15 days of treatment; Typhidot says IgM is negative & IgG is also negative.
So whether typhoid has resolved or person had no typhoid earlier (at time of widal)….
My doubt is simply that if IgG indicate remote infection then, should it not be positive in typhidot??…..or if it is negative then, there was no typhoid????
Please reply as soon as possible.
IgM Typhidot negative means the acute phase of the enteric fever is over.
Sir i have widal test with report of Typ O 1:20+ 1:40+ 1:80+ 1:160- 1:320- 1:640-
sir kindly explain that would i have typh fever? plz explain
i was completed 6 injection of shexon 1gm
and now i am getting ciprofloxacin tablet 500mg
Replied.
Sir i have widal test with report of Typ O 1:20+ 1:40+ 1:80+ 1:160- 1:320- 1:640-
sir kindly explain that would i have typh fever? plz explain
i was completed 6 injection of shexon 1gm
and now i am getting ciprofloxacin tablet 500mg
Your titer is 1:80, this is borderline, you should repeat widal after 5 to 7 days. If now it is 1:160, then it favors enteric fever. If it is the same at 1:80, then less likely of enteric fever.
Good Evening sir
My widal report is
S typhi o 1:320
S typhi H 1:80
S Para Typhi AH 1:20
S Para Typhi BH 1:20
But I don’t have fever, had slight back pain Body pain and cold
Kindly suggest
These values favor the diagnosis of enteric fever.
Good Evening sir
My widal report is
S typhi o 1:160
S typhi H 1:80
S Para Typhi AH 1:40
S Para Typhi BH 1:40
I have a low grade fever of 99-99.2 and body pain. Have done the antibiotics course using ceftas for 15 days but there is no improvement in fever. I have fever from almost a month now.
Kindly suggest
Please explain sir.. My father had gone trough Typhoid IGM TEST and it was negative and after 5 days we have done widal test and report is like
Salmonella typhi O (TO) Reactive upto Titre
1:160
Salmonella typhi H (TH) Reactive upto Titre
1:160
Salmonella paratyphi A, H (AH) Reactive upto Titre
1:80
Salmonella paratyphi B, H (BH) Reactive upto Titre
1:80
Note: 1. Titres 1:80 and above of “O” antigen & 1:160 and above
please explain us
Please let me know what ahppend after 5 days?
Sir
I hve typhoid in rage of typhi O 1:320
Typhi H 1:160
Paratyphi 1:80
Paratyphi 1:40
I’m taking Azifile I dnt hve fever but I got redpatches on my left ankle
Is that very critical Sir
O 1:320 is positive for typhoid fever. Ankle rashes may be due to drugs.
Sir Plz replay as soon as possible
replied.
Sir ,pls I need your help
S typhi(0) less than 80
Typhi 160 H
Paratyphi less than 80
S.Paratyphi less than 80
Bruccella app less than 80
1:80 test report is borderline, can take it as negative. Repeat the test after 5 to 7 days. If there is an increase in the value, then the test will be positive.
Good Evening sir
My widal report is
S typhi o 1:160
S typhi H 1:80
S Para Typhi AH 1:40
S Para Typhi BH 1:40
I have a low grade fever of 99-99.2 and body pain. Have done the antibiotics course using ceftas for 15 days but there is no improvement in fever. I have fever from almost a month now.
Kindly suggest
Your widal test shows a positive result. You should consult some good physicians to change the antibiotics or find the cause of fever,
Good Evening sir
My widal report is
S typhi O Antigen Negative 1:20 Dil
S typhi H Antigen Positive 1:40 Dil
S Para Typhi AH Antigen Negative 1:20 Dil
S Para Typhi BH Antigen Negative 1:20 Dil
I have a low grade fever of 98-98.4 and body pain. Have done the antibiotics course using for 5 days there is improvement in fever. Cough is persistent
Kindly suggest
You should check your blood CBC and have an Xray chest,
Hi sir 6 days back my result is
Salmonella typhi O antigen 1:80
Salmonella typhi H antigen 1:160
And now
O antigen 1:80
H antigen 1:40
But from two days my fever got 103 degrees and 101 I am using monochef 1 mg daily morning and evening from two days
Is it going to be cured? Please suggest the answer asap
Now your widal test doesn’t favor typhoid fever.
Please consult a physician for a fever.
Are you suggesting that the fever was not because of typhoid?
Hi sir, for example, the result of the widal test if the is like this:
Dilution: 1:20
Reaction: +++
Dilution: 1:40
Reaction: ++
Dilution: 1:80
Reaction: ++
Dilution: 1:160
Reaction: +
Dilution: 1:320
Reaction: +/-
Dilution: 1:640
Reaction: –
What is my approximate antibody titer? Does the +/- can be considered since it is the highest dilution where agglutination occurs, hence, <25% of agglutination is seen?
1:80 O antigen-positive is borderline. Needs repeat the test after 5 to 7 days. If it is 1:160, then it is positive. If it is again 1:80, then it is negative.
Thank you so much sir it helps me a lot
Thanks a lot sir if you’ll happen to address my concern ❤️
please can you let me know the issue?
Good morning sir,
My widal report is
S typhi o 1:320
S typhi H 1:160
S Para Typhi AH 1:20
S Para Typhi BH 1:20
CRP : 0.6 mg/dl is there any viral infection? Please suggest me
Your widal test is positive. I don’t think you have a viral disease.
Hi sir..
Widal report..
S. Typhi O 1:80
S. Typhi H 1:80
Para AH 1:80
Para BH 1:80
Kindly guide..
These numbers are borderline. Please repeat the test after 5 to 7 days. If titer (number) increases, then the widal test is positive, if remains the same, then is negative.
Thank you soo much for your response sir. please clarify me one thing sir, CRP level 0.6 mg/dl is normal level or infected. Widal test is positive then CRP is very high?
CRP level is normal. You have not given the widal test report.
Please Doctor My widal test reads
Salmonella typhi O: 1:20
Salmonella typhi H: 1:20. Please Doctor is this test negative or positive. From Ghana, Navrongo.
Widal test is negative.
Good Evening sir
My widal report is
S typhi o 1:320
S typhi H 1:160
S Para Typhi AH –
S Para Typhi BH –
But I have fever, had some cold.
Before 1 month report was same .
I take medicine and before 1 week
It is
S typhi o 1:160
S typhi H 1:160
S Para Typhi AH -1:40
Kindly suggest 1:40
Now it’s increase widal report is
S typhi o 1:320
S typhi H 1:160
S Para Typhi AH –
S Para Typhi BH –
Pls suggest what shows it and what I do for this .
Your widal test is positive. You need a good physician who should advise you the right antibiotics.
Sir I suffer from typhoid since 1 month
s typhi o 1:320
S typhi h 1:320
Before a month
Then 1 week it’s
S typhi o 1:160
S typhi h 1:160
And today it’s increase
S typhi o 1:320
S typhi h 1:160
Sir Please suggest me what should I do.
I think you need to consult a good physician who should give you the right antibiotics.
My sis having S. T. O 1:80dil
S. T. H 1:80 is thz typhoid positive or high
Pllzzz sir tell me
Please let me know your question?
These numbers are borderline, please repeat widal after 5 to 7 days. If the number increases then it is typhoid fever. If the number is the same or decreased, then not typhoid fever.
Replied to your question.
My cousin widal report is
T’H – positive upto 1:80
T’O – positive upto 1:160
What does this indicate?
It favors typhoid fever. O titer 1:160 comes in a positive range.
Tnku so much sir
Sir, I am experiencing mild fever and weakness from past 10days.
My widal test report says-
S.typhi O – 1.80
S.typhi H- 1.80
What does this means?
These figures are borderline. Please repeat the widal after 5 to 7 days. If this is 1:160, then definitely it is typhoid fever.
In immunological practical examination, two students were given a same patient serum to test for the presence of Salmonella antibodies. One of the students made dilutions to the given serum up to 1:620 and got a positive result, while the other made the dilutions till 1:160, and he got a negative result.
can you answer this question please
The answer is very simple. When the antibody titer is very high then this will be negative in early dilution. You have to make more dilution to see the positive result.
This is called the prozone phenomenon.
In February,salmonella typhi ‘O’- dilution-1:160
Salmonella typhi ‘H’-dilution 1:160
H titer 1:160 indicates past infection. What was your O antigen titer?
Indicate borderline result if there is rising titer then definitely Typhoid fever.
Sir my widal test for all components come to 1.80, im having fever since last 30 days, back pain, headache & once had blood clots from stool & throat. Im having antibiotics since last 2 days named cebosh cefixime 200mg. Plz suggest something as feeling very week internally.
Your Widal test does not favor Typhoid fever. Please repeat your widal and have an X-Ray chest. If your ESR is very high, then you must consult a good physician.
My S titer ‘O’Brien is 1:40 and ‘ H’ is 1:80 and Ah and Bhai are negative but one month before this tst my report was O and H both titer are 0:80..and between this period still now my fingers, wrist snd ankle were swollen and hv lot of pain in moving them what to do is it positive or not
Please see your email.
Sir my result was s typhi O 1:40 positive and s typhi H 1:40 positive . Do i have typhoid fever?
This widal test is negative for typhoid fever.
Thanks doctor but why they mentioned positive in my report . Can you explain me this ?
Thanks Dr. You are doing a great job.I have learnt a lot.
Best regards
Edwin from. Nigeria
Thanks. I need encouraging remarks like yours.
Thanks, I need encouraging remarks like yours.
Thank you doctor .. you are clearing many doubts .. May Allah reward you immensely for this help..
Thanks, You are welcome.
Hi Doctor,
My Father who is 65 years old, is also diabetic. He is having a fever for the last 7 days.
O is 1.8
H is 1.8
AH non-reactive
BH non-reactive
What does this mean? Can you please help?
If this is 1:80, then this is borderline for typhoid fever. You need to repeat after 5 to 7 days. If it is the same, then there is no typhoid fever; if it is increased to 1:160, then positive for enteric fever.
sir my mother is ill from months her widal is 320 after medicines ger fever went to 100 and today again her fever rises to 103 what should i do?
I think the widal test may be repeated, and she needs to have a workup for PUO (pyrexia due to unknown reason). She needs consultation by a good physician and the lab workup.
S. Typhi O = 1/40
S. Typhi H =1/40
Does this values confirm Typhoid?
S. Typhi O = 1/40 ( < 160 repeat after 1 week . Two fold increase )
S. Typhi H =1/40 ( in titre confirms the Salmonella infection )
S. Paratyphi AH Negative ( Single Widal estimation is of little )
S. Paratyphi BH Negative
Does this values confirm Typhoid?
No, With these figures, the widal test is negative.
sir i have s typhi o 1:320
s typhi h 1:160
along with covid what should i do please advice.. i have headache low fever weakness white tongue for about 28 days..
I think you need treatment by some good physician. Your widal test is positive. You have to keep an eye on your body’s oxygen level. Oximeters are available, and these are not costly. Keep an eye that your body oxygen level should not go below 90% (normal level is 95% to 100%). Now recommendations are giving steroids and antiviral therapy.
Again I will suggest consulting a physician.
Hello Sir,
From the Widal test I showed antibodies to Salmonella typhi (O type Vi) and Salmonella paratyphi (H type b). I was very sick while on vacation in South America one year ago. My doctor doesn’t seem to know how to treat this. Am I a carrier and what antibiotics do you recommend? Thank you so much.
Please, what are the values of the widal test? If these are around 1:40, then widal is negative. I am sure your physicians must be the better judge.
In the picture under “Widal test procedure:”. Why are 1:20, 40, 80 are negative?
Because of the concentration and the ratio of antigen and antibody, only then will you see agglutination when the ratio is adequate.
In the picture under “Widal test procedure:”. Why are 1:20, 40, 80 are negative?
Report for 4 year kid
Complaining pain near navel area
From.around 15 days with some time feeling like vomit .
Widal test
Salmonella typhi O. Reactive upto titre 1:80
Salmonella typhiH. Reactive upto titre 1:80
USG report
Liver normal in size portal vein and radical shows bright echogenic walls
Multiple enlarged mesenteric lymph nodes are seen largest at the root measuring 19*18
CBC.
PCV 40.30%
RBC count. 5.31mill/mm3
SGOT. 54UL
SGOT. 54
Please give your opinion as it is very hard to get blood test again done for kid.
Widal test O 1:80 is borderline. You have not written TLC and differential. Pain near the naval area needs to rule out appendicitis/ parasitic infestation. If the child has a problem for 14 days, then appendicitis is out. This child most likely may have a parasitic infestation. Please consult a good pediatrician.
Thank very much in replying very soon .I am very thankful to you ..your speedy reply on this post means a lot to me.I pary for your well being and progress in every aspect of your life .
Tlc 5 21
Lymphocytes 2.77
Eosinophils 0.04
Rest parameters in differtaial are ok
Child specialist has being consulted just received online report and was worried .
Thank very much in replying very soon .I am very thankful to you ..your speedy reply on this post means a lot to me.I pary for your well being and progress in every aspect of your life .
Tlc 5 21
Lymphocytes 2.77
Eosinophils 0.04
Rest parameters in differtaial are ok
Urine routine /culture… normal
If I plz tell what is Multiple enlarged mesenteric lymph nodes are seen largest at the root measuring 19*18.
hild specialist has being consulted just received online report and was worried .
TLC and DLC look normal. Rest mesenteric lymph nodes may be enlarged unless there is some history of fever and raised ESR. I will suggest you consult a good pediatrician for the possibility of parasitic infestation.
Thanks very much
Sir but my widal test o 1:40 and H 1:40. I have completed my course of 1 month and stopped taking medicine before 1 month now i chek my blood then results is 1:40 o, and 1:40 h what will I do plz sir ? Tell mr
This is the normal range. No need to worry.