Color Chart. This is a specially prepared multitest strip that is simply dipped into the urine specimen and then compared with the color values for the various tests on the accompanying chart. The color chart indicates pH values, and the numerical value should be reported.
The specific gravity of the specimen is the weight of the specimen as compared to an equal volume of distilled water. The specific gravity varies directly with the amount of solids dissolved in the urine and normally is from 1.015 to 1.030 during a 24-hour period.
The first morning specimen of urine is more concentrated and will have a higher specific gravity than a specimen passed during the day. A high fluid intake may reduce the specific gravity to below 1.010. In disease the specific gravity of a 24-hour specimen may vary from as low as 1.001 to as high as 1.060.
The specific gravity may be measured with the urinometer or the index refractometer, available as standard equipment at most duty stations. The refractometer may be held manually (fig. 6-11) or mounted on a stand like a microscope. The specific gravity is determined by the index of light refraction through solid material.
1. Pour urine into the cylinder until it reaches a point approximately 1 1/2 inches below the top of the cylinder. Insert the urinometer, making sure that it is floating freely. The cylinder should not overflow when the urinometer is immersed. Read the bottom of the meniscus.
2. If the specimen is cloudy, the urine should be centrifuged before specific gravity readings are taken. Cloudy urine tends to show low (and invalid) specific gravity.
Figure 6-11.Index refractometer.
1. Hold the index refractometer in one hand, and with the other hand and two applicator sticks, place a drop of urine on the glass section beneath the coverglass.
2. Hold the refractometer so that the light reflects on the glass section and look into the ocular end. Read the number that appears where the light and dark lines meet. This is the specific gratity.
Glucosuria is the presence of an abnormal amount of glucose in the urine. Traces of sugar are often found in normal urine, but are not enough to react to any of the routine tests for glucose. However, different sugars in the urine are of various clinical significance. When performing routine urinalysis, we can test for glucose, and any trace of glucose in the test suggests that something is wrong with the patients carbohydrate metabolism.
1. Test Strip, Glucose and Blood. This test is specific for glucose. Other sugars do not interfere.
a. Remove strip from container.
b. Dip into specimen. Remove and wait 30 seconds.
c. Immediately compare the test strip against the color chart.
d. Record results. Normal urine is negative for glucose.
e. If there is a positive reaction for glucose, a Clinitest is done for both confirmation and quantitation.
2. Urine-Sugar Test Tablets (Clinitest Tablets)
a. Place 5 drops of urine in a large test tube.
b. Add 10 drops of water and mix well.
c. Add one Clinitest tablet.
d. Put the tube in a rack. Let stand until the reaction is completed (foaming action has stopped).
e. Compare the color with the color chart and record the results.
f. If an orange color appears and then disappears, run the test again, diluted in half.
g. Be careful not to touch the end of the tube as it is extremely hot.