I've been ill for the past week with food poisoning, buthave had no time to go to the docto,. as my registered GP is in my home city and I am at university.

I've recovered now, but I was wondering if I were to go to the GP now, is there any way that they could tell of I was sick these last couple of days? Could this be done through a blood test or something similar? Ideally, I want proof that I have been ill this last week to claim mitigating circumstances for one of my exams, as I came down with the case of food poisoning two days before it. Will there be any trace of the bug left in my body?

  • If they could find the bug in your blood now you would still be very sick... Basically it depends on the sort and the severity of poisoning, that is the effects it had on your body - some cases might show changes in certain biochemical parameters (e.g. liver enzyme levels) - but for how long, for what sorts of poisoning and exactly which tests - I'll leave for an MD to answer (I'm from a different field).
    – Lucky
    Commented May 30, 2015 at 1:19

1 Answer 1


[I] was wondering if I were to go to the GP now is there any way they could tell that I was sick these last couple of days through some kind of blood test or something?

"Food poisoning" covers a vast number of illnesses, and whether it is detectable after your recovery depends on what type of illness caused it. For example, if your gastroenteritis was caused by a norovirus (formerly called Norwalk virus, the most common cause of food poisoning), a blood test for IgM (Immunoglobulin M) to the virus, indicating a recent illness, might be positive.

However, diagnosing after the fact in a short term and self-limiting illness like norovirus infection is harder than diagnosis during the illness (which requires just a small stool sample), unless the pathogen is known with certainty, and even then, there may not be a residual response to test.

Clearly, you will be paying for a large number of tests with only a chance that one of them will come up positive.

In terms of getting a doctor's note, it's best if you a) have a prior relationship with the physician, b) call him while you're sick (not after) or c) see a health care provider, go to the school health clinic, a walk-in clinic, or something similar.

Writing a note after the fact is a tricky area ethically. Many doctors who know and trust their patients will do it without hesitation. But I can understand others simply refusing the request for a post-illness work-up (which might be negative regardless) on the basis of cost and questionable need.

Or to use a medical metaphor, an ounce of prevention is better than a pound of cure.

Antibody Test To Detect Genogroup II Norwalk-Like Virus Infection
Assessment of a rapid immunochromatographic test for the diagnosis of norovirus gastroenteritis.

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