Over the next few weeks I will do a few articles on micro-organisms where I believe “overtesting” to occur and where there is ample scope to reduce the amount of tests without missing diagnoses.
The first of these tests I would like to look at is Hepatitis A.
There are a few reasons why Hepatitis A is over-tested which I will describe as follows:
- Hepatitis A is essentially a non-endemic disease in NZ, and is becoming so in many other developed countries. Occasionally there are clusters associated with a known imported case, but rarely in a non-traveller without a contact history. Requestors are not always aware of this.
- Hepatitis A almost always causes an acute illness with significant derangement of Liver Function Tests (LFTs) with the liver enzymes ALT and AST>100). Yet many times Hepatitis A is requested for the investigation of chronic mild derangement of LFTs.
- Hepatitis A is often requested as part of a “Hepatitis Screen” which may comprise a panel of Hepatitis A, B & C, even though they usually have completely different clinical presentations.
So what is the solution:
Firstly I am not a big fan of “Hepatitis Screens” and I think requestors should be made to request these tests individually.
Secondly, I would support rejection of the request for Hepatitis A in countries of low endemicity unless one of the following apply:
- The patient has a travel history.
- The patient has significant derangement of LFTs. (ALT or AST >100)
I think such measures (if not already used) applied in countries with low endemicity for Hepatitis A would see their testing volume for this test decrease by at least 2/3, and probably more, without adversely affecting the sensitivity of the test. On the contrary, the specificity of the test should increase due to the relatively higher prevalence of disease in the tested cohort.
In the era where health budgets are getting tighter, we need to start thinking seriously about how to test smarter…..Hepatitis A is a great place to start.