Urine Sugar Determination by the Two-drop Clinitest Method

Erroneous urine tests for sugar can result from many causes. The Clinitest method carried out in the usual recommended way (five drops of urine) is accurate in the 0 to 2 per cent sugar concentration range. Over 4 per cent, there is a reversal of color which can be mistaken for 0.75 or 1 per cent and which is referred to as “pass through.” When two drops of urine are used instead of five, the range of Clinitest change is extended from 0 to 5 per cent and the “pass through” delayed until a concentration over 10 per cent sugar is reached. In 191 urines from diabetic children, the confusing “pass through” was found to occur seventy times when the urine was tested by the “five-drop method.” It did not occur in testing the same urines using the “two-drop method.” Quantitative chemical analysis established the range of these two methods. It is recommended that the “two-drop method” should replace the “five-drop method.”