MODEL RELEASED. Glucose test during pregnancy. Pregnant woman checking the colour of a reagent strip used in a Clinistix urine test. The Clinistix test detects glucose sugar levels in urine. The brown colouration on the reagent strip indicates a positive (abnormal) result. In diabetic patients, levels of glucose in the urine and blood are abnormally raised. This is due to insufficient production of the hormone insulin which allows the body to store and metabolise glucose. Pregnant women can sometimes develop temporary diabetes (gestational diabetes). It is therefore necessary to test for diabetes during pregnancy.