Urinalysis

Urinalysis is a diagnostic physical, chemical, and microscopic examination of a urine sample (specimen). Specimens can be obtained by normal emptying of the bladder (voiding) or by a hospital procedure called catheterization.

Urinalysis purpose General evaluation of health. Diagnosis of metabolic or systemic diseases that affect kidney function. Diagnosis of endocrine disorders. Twenty-four-hour urine studies are often ordered for these tests. Diagnosis of diseases or disorders of the kidneys or urinary tract. Monitoring of patients with diabetes. Testing for pregnancy. Screening for drug abuse.

Collection of Voided specimens First morning sample Midstream, clean catch collection Minimum volume of 3 ml (1 ml for children) Analysis within 1-2 hours or refrigerate

Testing techniques Dipsticks are thin strips of plastic that change color in the presence of specific substances. Dipsticks can be used to measure: Specific gravity Acidity of the urine (its pH) The presence of blood, Protein, Sugar, Substances produced during the breakdown of fatty acids (ketones). Under a microscope to determine whether it contains blood cells, crystals, or small pieces of fibrous material (casts).

Normal Values Normal urine may vary in color from almost colorless to dark yellow. Some foods (like beets and blackberries) may color the urine red. The urine specific gravity ranges between 1.005 and 1.030 (higher numbers mean a higher concentration). The specific gravity varies depending on the time of day, amount of food and liquids consumed, and the amount of recent exercise. The urine pH is also influenced by a number of factors. Generally the normal pH range is from 4.6 to 8.0, with an average of 6.0. There is usually no detectable urine glucose, urine ketones, or urine protein. There are usually no RBCs in urine Hemoglobin is not normally found in the urine. Bilirubin is normally not detected in the urine. There may be a trace of urobilinogen in the urine. Nitrites and white blood cells (leukocytes) are not normally present in the urine.

Test Reference Range Color Straw - Dark yellow Appearance Clear – Hazy Specific Gravity 1.003-1.03 pH 4.5-7.8 (average 6.0) Protein Negative Glucose Ketones Bilirubin blood Urobilinogen 0.1-1.0 EU/dL WBCs 0-4/hpf RBCs female: 0-5/hpf; male: 0-3/hpf Casts 0-4/lpf Bacteria EU = Ehrlich Units (1 mg) RBC are reported as number seen per power field (HPF): hpf = High Power Field (400x) lpf = Low Power Field (100X) The specific gravity of a substance is a comparison of its density to that of water.