Urinalysis Involves examination of the urine for overall characteristics, including appearance, pH, specific gravity, and osmolality as well as microscopic evaluation for the presence of normal and abnormal cells

Appearance – Normal urine is clear. Cloudy urine (Phosphaturia) is not always pathologic, related only to the precipitation of phosphates in alkaline urine. Normal urine may also develop cloudiness on refrigeration or from standing at room temperature. Abnormally cloudy urine – due to pus (Pyuria), blood, epithelial cells, bacteria, fat, colloidal particles, phosphate, or lymph fluid (Chyluria)

Odor – normal urine has a faint aromatic odor. Characteristic odors produced by ingestion of asparagus, thymol. Cloudy urine with ammonia odor – urea-splitting bacteria such as Proteus, causing UTIs. Offensive odor – may be due to bacterial action in presence of pus.

Color – shows degree of concentration and depends on amount voided. Normal urine is clear yellow / amber because of the pigment urochrome. Dilute urine is straw-colored. Concentrated urine is highly colored; as a sign of insufficient fluid intake. Cloudy or smoky colored – may be from hematuria, spermatozoa, prostatic fluid, fat droplets, chyle. Red / red brown – due to blood pigments, porphria, transfusion reaction, bleeding lesions in urogenital tract, some drugs and food (beets).

f. Yellow-brown / green-brown – may reveal obstructive lesion of bile duct system / obstructive jaundice. g. Dark brown / black – due to malignant melanoma, leukemia.

pH of Urine – reflects the ability of kidney to maintain normal hydrogen ion concentration in plasma and extracellular fluid; indicates acidity / alkalinity of urine. pH should be measured in fresh urine because the breakdown of urine to ammonia causes urine to become alkaline. Normal pH is around 6 (acid); may normally vary from 4.6 – 7.5 Urine acidity / alkalinity has relatively little clinical significance unless the pt is on a special diet / therapeutic program / is being treated for renal calculous disease.

Specific gravity – reflects the kidney’s ability to concentrate / dilute urine; may reflect degree of hydration / dehydration. Normal specific gravity ranges from 1.005 – 1.025. Specific gravity is fixed at 1.010 in chronic renal failure. In a person eating a normal diet, inability to concentrate / dilute urine indicates disease.

Osmaolality is an indication of the amont of osmotically active particles in urine ( number of particles per unit volume of water)