Saliva on Hemastix Produces False-Positive Results for Blood

To the Editor: I have had the opportunity to see three patients in whom therapy was instituted for upper gastrointestinal blood loss according to analysis of an emesis specimen with Hemastix (Ames Labs, Elkhart, Ind.). These reagent strips are approved for use only in urine, and their accuracy in other body fluids is not established for clinical use. We had six normal volunteers apply saliva to blood-sensitive urinalysis strips from two companies. In all cases a strong result for blood was obtained. This false-positive reaction could lead to inappropriate medical therapy. Clinicians should be advised that only tests approved for.