A trace reaction on a reagent strip and a high Clinitest reaction is observed. What could cause this to happen?
In this case, these two reactions would indicate the presence of glucose and other reducing substances.
However, there are several explanations for the finding of conflicting results between the two glucose tests. The Clinitest is not as sensitive as the glucose oxidase test, so the finding of a 1+ reagent strip reading and a negative Clinitest should not be surprising. A strongly positive reagent strip and a negative Clinitest, however, should cause concern about possible contamination by strong oxidizing agents.
The most significant discrepancy is the negative reagent strip with a positive Clinitest. Although interfering substances affecting either test may cause this problem, the most frequent cause is the presence of other reducing sugars in the urine. As a nonspecific test for reducing substances, Clinitest is subject to interference from other reducing sugars, including galactose, lactose, fructose, maltose, pentoses, ascorbic acid, certain drug metabolites, and antibiotics such as the cephalosporins. Therefore, Clinitest does not provide a confirmatory test for glucose.