An Atypical Rant About the Widal Test

Dear Reader

This letter may come across as a bit harsh.

So, I am starting it off with an apology. I am sorry that you didn’t receive last week’s letter. I had a lot on my plate, and I guess somewhere along the line, I burnt out.

But I am back now, and I am angry.

Sometime last week, I came across a post. In this post, a medical doctor claimed that the Widal Test is useless and should be rendered obsolete.

He went further to say that laboratories that still carried out this investigation were only doing so to extort individuals.

Then, he said, that typhoid is extremely rare, and that all we are succeeding in doing is pumping people with antibiotics, which could lead to resistance.

Now, many people were in the comment section agreeing with him, including medical laboratory scientists.

And that got me angry. Because not only were many of the things he said untrue, they were more than a tad contradictory.

The Widal test is a serological test used to help diagnose typhoid fever, which is caused by the bacterium Salmonella enterica serotype Typhi (and sometimes Paratyphi A, B, or C).

It’s a lot of medical talk, but basically, the Widal test helps check for enteric fever, more commonly known as typhoid fever.

I will be the first person to agree that the Widal test has limitations. It has low sensitivity and specificity, and so can lead to false positives and false negatives.

I will also agree that in ideal conditions, it should not be the investigation of choice for testing enteric fever. But the conditions are far from ideal.

Most times, patients do not have the time or resources to opt for a blood and stool culture. That is where the Widal test, regardless of its limitations, can be useful.

And like every laboratory investigation, interpretation and utility boil down to the medical laboratory scientist and the clinician.

No laboratory test should be treated in isolation. The clinician should compare the results with a Full Blood Count and the patient’s history.

If the patient has recently treated typhoid, then what the test is picking up might be residual antibodies.

The clinician might consider managing the patient’s symptoms until they can carry out paired serology. However, this is usually not feasible.

Now, this brings me to the last point the doctor made in his post. He said that the reason you feel better after taking typhoid medication is that the treatment probably addressed something else.

Antibodies detected by the Widal test are not exclusive to Salmonella Typhi. It can also pick up other Salmonella infections and even enteric infections.

The good thing about this is that the treatment for these infections is similar. So, if this treatment is addressing a condition that shows similar symptoms to typhoid fever, where is the talk about pumping people with antibiotics coming from?

So, while I agree that the Widal test is not the best laboratory investigation, it is not useless and, when used properly, can still be an adequate diagnostic tool.

P.S. What I am Reading this Week

This week, I picked up Adesuwa O’Man Nwokedi’s No Perfect Love. A book about love’s enduring strength and a woman’s choice.

Till next time

Cherechi