For example, a method to obtain an uncontaminated urine sample involves passing a catheter through the urethra into the bladder. Urine cultures , in which bacteria from a urine sample are grown in a laboratory, are done to diagnose a urinary tract infection Overview of Urinary Tract Infections UTIs In healthy people, urine in the bladder is sterile—no bacteria or other infectious organisms are present.
The tube that carries urine from the bladder out of the body urethra contains no bacteria Cultures are not part of routine urinalysis. The sample of urine must be obtained by the clean-catch method see sidebar Obtaining a Clean-Catch Urine Sample Obtaining a Clean-Catch Urine Sample Urinalysis, the testing of urine, may be necessary in the evaluation of kidney and urinary tract disorders and can also help evaluate bodywide disorders such as diabetes or liver problems. Uncircumcised men should retract their foreskin to cleanse the head of the penis.
Urination is resumed, and a sample is collected from the stream into a sterile cup. Usually the sample is obtained before the stream ends midstream. Chemical tests look for protein, glucose sugar , ketones, blood, and other substances. These tests use a thin strip of plastic dipstick impregnated with chemicals that react with substances in the urine and quickly change color. Sometimes the test results are confirmed with more sophisticated and accurate laboratory analysis of the urine.
Examining the urine under a microscope may be done to check for the presence of red and white blood cells, crystals, and casts impressions of the kidney tubules created when urinary cells, protein, or both precipitate out in the tubules and are passed in the urine. Protein in the urine proteinuria can usually be detected by dipstick when present in large amounts. Protein may appear constantly or only intermittently in the urine, depending on the cause.
Proteinuria may occur normally after strenuous exercise, such as marathon running, but is usually a sign of a kidney disorder.
Small amounts of protein in the urine may be an early sign of kidney damage due to diabetes. Such small amounts may not be detected by dipstick. In these cases, urine will need to be collected over a period of 12 or 24 hours and tested by a laboratory. Glucose in the urine glucosuria can be accurately detected by dipstick.
The most common cause of glucose in the urine is diabetes mellitus Diabetes Mellitus DM Diabetes mellitus is a disorder in which the body does not produce enough or respond normally to insulin, causing blood sugar glucose levels to be abnormally high.
Urination and thirst are Also, presence of glucose does not necessarily indicate diabetes or another problem. It's used to detect and manage a wide range of disorders, such as urinary tract infections, kidney disease and diabetes. A urinalysis involves checking the appearance, concentration and content of urine.
For example, a urinary tract infection can make urine look cloudy instead of clear. Increased levels of protein in urine can be a sign of kidney disease. Other tests, such as pregnancy testing and drug screenings, might rely on a urine sample, but these tests look for substances that aren't included in a typical urinalysis. If you're having only a urinalysis, you can eat and drink before the test. If you're having other tests, you might need to fast before the test. Your health care provider will give you specific instructions.
Many drugs, including nonprescription medications and supplements, can affect the results of a urinalysis. Before a urinalysis, tell your doctor about medications, vitamins or other supplements you take. You might collect a urine sample at home or at your health care provider's office. Providers typically give out containers for urine samples. You might be asked to collect the sample at home first thing in the morning, when your urine is more concentrated.
You might be instructed to collect the sample midstream, using a clean-catch method. This method involves the following steps:. In some cases, if needed, your provider can insert a thin, flexible tube catheter through the urinary tract opening and into the bladder to collect the urine sample.
The urine sample is sent to a lab for analysis. You can return to your usual activities immediately. At many institutions, pharmacists play a key role in reviewing positive urinalysis and urine culture results as a part of antimicrobial stewardship and clinical activities. It can be tempting to simply recommend an antibiotic based on test results, but in order to prevent overtreatment of asymptomatic patients, a careful review of symptoms should also be conducted. Pharmacists can be proactive in implementing antibiotic prescribing pathways that provide empirical antibiotic recommendations utilizing local susceptibility data.
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