Urinalysis

A complete urinalysis comprises: gross appearance, USG, several biochemical tests using commercial reagent strips, and microscopic examination of the urine sediment. Regardless of the volume of urine that is submitted, laboratories conduct the urinalysis using a standard volume, often 3 mL, to enable comparison of sediment findings.

Urine is collected in a variety of ways including: free flow, catheterization, cystocentesis, and from various surfaces following urination. The interpretation of several findings will vary with the method of collection underscoring the importance of providing this information to the diagnostic laboratory. For example, erythrocytes are often present iatrogenically in samples obtained by cystocentesis and catheterization. Additional information may help exclude pathologic causes of hematuria under these circumstances. Erythrocytes in a voided sample suggest bleeding from the urinary or genital tract, or both. The presence of leukocytes and bacteria in a sample obtained by cystocentesis is consistent with urinary tract inflammation and infection. The same finding in a catheterized or voided sample could be due to urinary tract inflammation/infection, genital tract inflammation/infection, or contamination of the sample from the distal urethral opening.