Extensive vs Focused Testing: Which is Best for Liver Disease?

Testing for elevated liver enzymes should be deliberate and focused, as limited testing can save time and money and prevent false positives according to a new study.

“There is a widespread perception that when it comes to liver testing, more is always better. but these data show otherwise,” said lead study author Elliot B. Tapper, MD, of the division of gastroenterology at the University of Michigan in Ann Arbor. “Instead, it is the patient’s unique story and presentation that determines the appropriate amount of testing. Testing patients for rare diseases when they present all the clues for common diseases is more likely to expose them to the scare of a false-positive than an alternate diagnosis.”
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The researchers simulated the evaluation of 10,000 adult outpatients with elevated alanine aminotransferase to compare 2 evaluative strategies: testing for all diseases at once (extensive) or just common diseases first (focused).

Model inputs employed population-based data from the US (National Health and Nutrition Examination Survey) and Britain (Birmingham and Lambeth Liver Evaluation Testing Strategies). They followed patients until a diagnosis was provided or a diagnostic liver biopsy was considered. The primary outcome was US dollars per diagnosis. Secondary outcomes included doctor visits per diagnosis, false-positives per diagnosis, and confirmatory liver biopsies ordered.

The extensive testing strategy required the lowest monetary cost, yielding diagnoses for 54% of patients at $448/patient compared to 53% for $502 under the focused strategy. The extensive strategy also required fewer doctor visits (1.35 vs 1.61 visits/patient). However, the focused strategy generated fewer false-positives (0.1 vs 0.19/patient) and more biopsies (0.04 vs 0.08/patient). Focused testing becomes the most cost-effective strategy when accounting for pre-test probabilities and prior evaluations performed. Focused testing also is the most cost-effective strategy in the referral setting where assessments for viral hepatitis, alcoholic, and non-alcoholic fatty liver disease already have been performed.

Dr Tapper described 2 major take-home messages for primary care providers:

“First, because the harms of false positives are real, it is worth pausing before testing to discuss the consequences of the blood tests in the context of data about disease prevalence and the specifics of the patient’s situation,” he said. “For instance, fatty liver disease is the most common liver disease in the US. So, if you meet a middle-aged patient with diabetes, bad cholesterol, and excess weight with elevated liver enzymes, it is a great idea to exclude alcohol by history and hepatitis C, but it is also a good idea to focus the patient’s efforts on the most likely culprit.”

“Second, for patients with really high liver enzymes, some of the most common and serious causes don’t have blood tests at all,” he concluded. “These include ischemic hepatitis—which needs a history and physical above all—and gallstone disease, which needs imaging.”

—Mike Bederka

Reference:

Tapper EB, Saini SD, Sengupta N. Extensive testing or focused testing of patients with elevated liver enzymes. J Hepatol. 2017 Feb;66(2):313-319. doi: 10.1016/j.jhep.2016.09.017.