Laboratory Tests of Urine No patient health evaluation is complete without the findings of laboratory tests of blood and urine.The doctor
Laboratory Tests of Urine
No patient health evaluation is complete without the findings of laboratory tests of blood and urine.
The doctor or his assistant may give special instructions about food and water intake well in advance of the time for delivering a urine specimen because those factors can
influence the chemical makeup of the sample. The time of day of the
collection also can affect the composition of the urine sample ; urine voided early in the morning is likely to be more acid in content, while urine collected after a meal may be
more alkaline. Thus, for a routine physical, the doctor may advise that a urine sample be taken at his office inumber the morning. But that nothing be eaten since the previous evening meal.
The doctor also may want not the first, but the second specimen of the day. In some cases, depending upon the patient’s complaint, the doctor may request a collection of all the urine voided during a period of 12 or 24 hours.
WHAT ARE THE CHEMICAL CONTENT OF A URINE ?
A typical urine sample is, of course, mostly water. But it also may contain about two dozen identifiable minerals and other chemicals, including sodium, potassium, calcium, sulfur, ammonia, urea, and several different acids. A urine sample can range in color from pale straw to dark amber, depending upon the concentration,
It also can be other colors, including orange or blue, Or even colorless
depending upon foods eaten, medications taken, diseases, or exposure to toxic substances.
WHAT ARE THE APPEARANCE AND ACIDITY OF URINE ?
The urine sample’s general appearance,
including color, is noted by the laboratory technician. The sample also is tested for acidity or alkalinity, normal urine being just slightly on the acid side of neutral. Urine
that is definitely acidic can be a sign of a variety of disorders, including certain metabolic problems. Urine that is markedly on the alkaline side of neutral also can suggest a number of possible disorders, including an infection of the urinary tract.
Alkalinity could also be caused by certain
medications, or even by the parent’s use of large doses of bicarbonate of soda. Foods rich in protein can make the urine more acidic, while citrus fruits and some vegetabies may tend to make a patient’s