Urinalysis - The Carter Center

2. Dip part of the tape into the urine specimen; remove it
immediately.
3. Wait for 30 seconds; then observe the appearance of any green
color.
4. Record the result as positive or negative. If the test area remains
yellow after 30 seconds, the result is negative. If any green color
is present at this time, the result is positive.
C. Diastix Reagent Strip for Glucose
Principle
Diastix is a specific test for glucose based on the use of glucose
oxidase, which is impregnated on the reagent strip. The chemical
reaction is the same as for clinistix, the difference being the chromogen
system used to indicate the presence of glucose. The reagent area
contains glucose oxidase, peroxidase, a blue background dye, and
potassium iodide as the chromogen. In a positive reaction oxidation of
potassium iodide results in the formation of free iodide, which blends
with the blue background dye to give shades of green through brown.
(The Boeringer dip-strip Test is also based on the same principle). As
with clinistix, large amounts of ascorbic acid may give falsely negative or
delayed results for glucose. This suppression is not as great as with
clinistix, but it may cause problems. Bleach and hydrogen peroxide
may cause falsely positive reactions, as with Clinistix.
Diastix has the advantage of being suitable as a screening test for the
presence of glucose in the urine, and giving a rough estimate of the
amount of glucose present. It detects as little as 100 mg of glucose per
100 ml of urine. However, urine specimens from pediatric patients must
be subjected to a non-specific test for urinary sugar (Clinitest or
Benedict's test) in addition to the specific glucose screening test in order
to detect the presence of sugars other than glucose.
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