Definition Results Specialists The Procedure Pros & Cons Interpretation Other Urine Tests
Definition Results Specialists The Procedure Pros & Cons Interpretation Other Urine Tests Center Comments
A urinalysis is simply an analysis of the urine. It is a very common test that can be performed in many health care settings, including doctors' offices, urgent care facilities, laboratories, hospitals, and even at home.
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A urinalysis test is performed by collecting a urine sample from the patient in a specimen cup. Usually only small amounts (30-60 mL) may be required for urinalysis testing. The sample can be either analyzed in the medical clinic or sent to a laboratory to perform the tests. Urinalysis is abbreviated UA.
UA is in general easily available and relatively inexpensive. It is also a simple test and can provide many useful information about various diseases and conditions. Some physicians refer to urinalysis as “a poor man's kidney biopsy” because of the plethora of information that can be obtained about the health of the kidney or other internal diseases by this simple test.
Urine can be evaluated by its physical appearance (color, cloudiness, odor, clarity), also referred to as a macroscopic analysis. It can be also analyzed based on its chemical and molecular properties, including microscopic assessment.
Urinalysis is ordered by doctors for a number of reasons, including the following:
Urinalysis (Urine Test)
A doctor may simply perform a urine dipstick test in the office. Only a few minutes are needed to obtain results. Your health-care provider may also send a urine sample to the lab for culture testing (see below). These results take a few days to come back. This tells the doctor the exact bacteria causing the infection and to which antibiotics these bacteria have resistance or sensitivity. The culture is usually sent for special populations, including men, because they are less likely to get UTIs. It is not necessary to send a culture for everyone because the majority of UTIs are caused by the same bacteria.
The single most important lab test is urinalysis. A urine sample will be tested for signs of infection, such as the presence of white blood cells and bacteria.
Read more about diagnosing urinary tract infections »
Urinalysis can disclose evidence of diseases, even some that have not caused significant signs or symptoms. Therefore, a urinalysis is commonly a part of routine health screening.
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Urinalysis is commonly used to diagnose a urinary tract or kidney infection, to evaluate causes of kidney failure, to screen for progression of some chronic conditions such as diabetes mellitus and high blood pressure (hypertension).
It also may be used in combination with other tests to diagnose some diseases. Additional tests and clinical assessment are often required to further investigate findings of urinalysis and ultimately diagnose the causes or specific features of underlying problems. For example, urine infection is generally diagnosed based on results of urinalysis. However, urine culture is often ordered as a follow-up test to confirm the diagnosis and to identify the bacteria that may be causing the infection. Other examples include kidney stones, inflammation or the kidneys (glomerulonephritis), or muscle breakdown (rhabdomyolysis).
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Urinalysis is done by collecting a urine sample from a patient. The optimal sample tends to be an early morning urine sample because it is frequently the most concentrated urine produced in the day. Typically, no fasting is required before the collection of urine sample and routine medications can be taken before the test, unless otherwise instructed by the ordering physician.
Methods of collection are slightly different for female and male patient.
For females, the patient is asked to clean the area around the urethra with a special cleansing wipe, by spreading the labia of the external genitals and cleaning from front to back (toward the anus). The cleaning hand is then used to maintain the spread while the cup is held by the other hand to collect the sample.For men, the tip of the penis may be wiped with a cleansing pad prior to collection.The urine is then collected in a clean urine specimen cup while the patient is urinating. It is best to avoid collecting the initial stream of urine. After the initial part of urine is disposed of in the toilet, then the urine is collected in the urine container provided. Once about 30 mL to 60 mL (roughly 3 to 5 tablespoons) are collected in the container for testing, the remainder of the urine may be voided in the toilet again. This is called the midstream clean catch urine collection.
The collected urine sample should be taken to the laboratory for analysis, typically within one hour of collection. If transportation to the lab could take more than one hour, then the sample may be refrigerated.
In some patients who are unable to void spontaneously or those who are not able to follow instructions other methods may be used, such as placing a catheter (a small rubber tube) through the outside opening to the bladder (urethra) to collect the sample directly from the bladder.