A "UA" (urine analysis) or urinalysis is an array of tests performed on urine and one of the most common methods of medical diagnosis. A part of a urinalysis can be performed by using urine dipsticks, in which the test results can be read as color changes.
Medical Urinalysis (urine analysis) Test
A typical medical urinalysis (UA) or urine analysis usually includes:
- a description of color and appearance.
- specific gravity - normally 1.002 to 1.028. This test detects ion concentration of the urine. Small amounts of protein or ketoacidosis tend to elevate results of the specific gravity. Specific gravity is an expression of the weight of a substance relative to the weight of an equal volume of water. Water has a specific gravity of one. The specific gravity of your urine is measured by using a urinometer. Knowing the specific gravity of your urine is very important because the number indicates whether you are hydrated or dehydrated. If the specific gravity of your urine is under 1.007, you are hydrated. If your urine is above 1.050, you are dehydrated. See also Specific Gravity Test
- pH - normally 4.8 to 7.5. See, Urine PH Test for more information.
- ketone bodies - normally negative (absent). When there is carbohydrate deprivation, such as starvation or high protein diets, the body relies increasingly on the metabolism of fats for energy. This pattern is also seen in people with the disease diabetes mellitus, when a lack of the hormone insulin prevents the body cells from utilizing the large amounts of glucose available in the blood. This happens because insulin is necessary for the transport of glucose from the blood into the body cells. The metabolism of fat proceeds in a series of steps. First, triglycerides are hydrolyzed to fatty acids and glycerol. Second the fatty acids are hydrolyzed into smaller intermediate compounds (acetoacetic acid, betahydroxybutyric acid, and acetone). Thirdly, the intermediate products are utilized in aerobic cellular respiration. When the production of the intermediate products of fatty acid metabolism (collectively known as ketone bodies) exceeds the ability of the body to metabolize these compounds they accumulate in the blood and some end up in the urine (ketonuria).
- proteins - normally negative (absent)
- Albustix Test - Since proteins are very large molecules (macromolecules), they are not normally present in measurable amounts in the glomerular filtrate or in the urine. The detection of proteins in your urine may indicate that the permeability of the glomerulus is abnormally increased. This may be caused by renal infections or it may be caused by other diseases that have secondarily affected the kidneys such as diabetes mellitus, jaundice, or hyperthyroidism.
- nitrites. See, Nitrite Test for more information on nitrites in human urine.
- Bilirubin - The fixed phagocytic cells of the spleen and bone marrow destroy old red blood cells and convert the heme groups of hemoglobi to the pigment bilirubin. The bilirubin is secreted into the blood and carried to the liver where it is bonded to (conjugated with) glucuronic acid, a derivative of glucose. Some of the conjugated bilirubin is secreted into the blood and the rest is excreted in the bile as bile pigment that passes into the small intestine. The blood normally contains a small amount of free and conjugated bilirubin. An abnormally high level of blood bilirubin may result from: an increased rate of red blood cell destruction, liver damage, as in hepatitis and cirrhosis, and obstruction of the common bile duct as with gallstones. An increase in blood bilirubin results in jaundice, a condition characterized by a brownish yellow pigmentation of the skin and of the sclera of the eye.
- Icotest - The test used to detect the destruction of old Red Blood Cells (RBC) in the urine.
- glucose - normally negative (absent)
- Benedict's Test - Although glucose is easily filtered in the glomerulus, it is not present in the urine because all of the glucose that is filtered is normally reabsorbed from the renal tubules back into the blood.
- Hemoglobin Test - Hemolysis in the blood vessels, a rupture in the capillaries of the glomerulus, or hemorrhage in the urinary system may cause hemoglobin to appear in your urine.
- RBC number
- WBC number
- hCG - normally absent, this hormone appears in the urine of pregnant women. A Home Pregnancy Test commonly detect this substance.
A urine sample is submitted for analysis. Below, a urine sample is about to be examined under a phase-contrast microscope using a Neubauer counting chamber. The urine is under the cover slide, in the upper segment formed by the H-shaped grooves.
The numbers and types of cells and/or material such as urinary casts can yield a great detail of information and may suggest a specific diagnosis.
- Hematuria - associated with kidney stones, infections, tumors and other conditions
- Pyuria - associated with urinary infections
- eosinophiluria - associated with allergic interstitial nephritis, atheroembolic disease
- Red blood cell casts - associated with glomerulonephritis, vasculitis, malignant hypertension
- White blood cell casts - associated with acute interstitial nephritis, exudative glomerulonephritis, severe pyelonephritis
- crystalluria -- associated with acute urate nephropathy (or "Acute uric acid nephropathy", AUAN)
- [[calcium oxalate monohydrate) - associated with ethylene glycol toxicity
UA Test (urine analysis) As Part Of A Medical Procedure
Female Urinary Tract
Male Urinary Tract
Urinalysis (urine analysis) is the physical, chemical, and microscopic examination of urine. It involves a number of tests to detect and measure various compounds that pass through the urine.
How the Test is Performed
A urine sample is needed. Your health care provider will tell you what type of urine sample is needed. For information on how to collect a urine sample, see Urine Sample Collection:
There are three basic steps to a complete urinalysis (urine analysis):
- Physical color and appearance:
- What does the urine look like to the naked eye?
- Is it clear or cloudy?
- Is it pale or dark yellow or another color?
- Microscopic appearance:
- The urine sample is examined under a microscope. This is done to look at cells, urine crystals, mucus, and other substances, and to identify any bacteria or other microorganisms that might be present.
- Chemical appearance:
- A special stick ("dipstick") tests for various substances in the urine. The stick contains little pads of chemicals that change color when they come in contact with the substances of interest.
How to Prepare for the Test
Certain medicines change the color of urine, but this is not a sign of disease. Your doctor may tell you to stop taking any medicines that can affect test results.
Medicines that can change your urine color include:
How the Test Will Feel
The test involves only normal urination, and there is no discomfort.
Why the Test is Performed
A urinalysis may be done:
- As part of a routine medical exam to screen for early signs of disease
- If you have signs of diabetes or kidney disease, or to monitor you if you are being treated for these conditions
- To check for blood in the urine
- To diagnose a urinary tract infection
Normal urine may vary in color from almost colorless to dark yellow. Some foods (like beets and blackberries) may turn the urine a red color.
Usually, glucose, ketones, protein, bilirubin, are not detectable in urine. The following are not normally found in urine:
- Red blood cells
- White blood cells
Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
What Abnormal Results Mean
For specific results, see the individual test article:
|Bilirubin - urine||Glucose - urine|
|Protein - urine||Red blood cells in urine test|
|Urine ketones||Urine protein|
If a home test is used, the person reading the results must be able to distinguish between different colors, since the results are interpreted using a color chart.
Urinalysis can reveal diseases that have gone unnoticed because they do not produce striking signs or symptoms. Examples include diabetes mellitus, various forms of glomerulonephritis, and chronic urinary tract infections.
The most cost-effective device used to screen urine is a paper or plastic dipstick. This microchemistry system has been available for many years and allows qualitative and semi-quantitative analysis within one minute by simple but careful observation. The color change occurring on each segment of the strip is compared to a color chart to obtain results. However, a careless doctor, nurse, or assistant is entirely capable of misreading or misinterpreting the results. Microscopic urinalysis requires only a relatively inexpensive light microscope.