Urine strips for making Diagnosis: Part 2

Urine glucose is the most frequent diagnosis sought out on a urine strip. Urine strips readily identify glucose in the urine; however, for the result to be reliable one has to ensure that the strip has not expired. If the enzymatic action of enzymes is altered on the pad, then the results may be spurious.

Urine strips are quite sensitive to glucose in the urine and this is one of the fastest and inexpensive ways to check for glucose. Abnormal glucose may be seen in diabetes, pregnancy or after a heavy diet. The sensitivity of urine strip to glucose is decreased when the urine has high specific gravity or ascorbic acid concentration is high

Bilirubin levels on a urine strip are often unreliable. The best way to use urinary bilirubin level is to correlate them with clinical findings and laboratories values.

The occult blood test on a urine strip may detect red blood cells, free hemoglobin or myoglobin. The test is very sensitive and quite useful. Blood may be seen in the urine due to a kidney stone, urinary tract infection, break down of muscle, or red blood cells. When urine has high specific gravity it reduces sensitivity of the strip, while ascorbic acid may cause a falsely negative test.

The protein test pad only gives a rough estimate of protein in the urine. However, false positives may occur if the urine pH is very alkaline. Protein may occur in urine from a variety of conditions including:

- Position
- Strenuous exercise
- Extremes of temperature (too hot or too cold)
- Pregnancy
- Low blood pressure
- Liver cirrhoses
- Renal failure
- Upper respiratory tract infection
- Immune complex disorders
- Sepsis

The urine strip reagent is highly sensitive to albumin and less to globulin