Urine passed into a clean vessel is suitable for routine urine testing. Special me hods of collection designed to reduce contamination are desirable for microscopic examination, and essential for bacteriological examination. The urine should be examined physically, chemically, microscopically and bacteriologically.
Naked Eye Examination: Quantity, colour, transparency, specific gravity, naked-eye characteristics of the deposits, are noted. The normal quantity of urine passed daily varies widely from 700 to 2500 ml, depending on the fluid intake and the weather.
Chemical Examination: Many of the traditional chemical teats for urinary constituents have been replaced for routine purposes by commercial tablets or reagent stick or strip tests.
Commonly tested biochemicals in urine are sugar and albumin; others are blood derivatives such as bile pigments and ketones.
Microscopic Examination: Urine is centrifuged at 1000-1500 rpm for ten minutes and the deposits examined microscopically. Red blood cells, white blood cells, epithelial cells, crystals and bacteria are looked for and reported.
Bacteriological Examination: A midstream urine specimen is collected after the vulva or glans penis has been cleaned with tap-water. It is suitable for most bacteriological purposes. Antiseptic solutions are not used for cleaning, as they may kill the bacteria present in the urine.
The most satisfactory specimen for cultures or tests is the one collected first after arising from sleep, because bacteria in the bladder have been able to multiply undisturbed for several hours. Presence of many bacteria in the urine indicates an infection.