Urine Analysis Complete

Also Known as:  Urine Test, Urine Analysis, UA

What is a Urinalysis test?

A urinalysis is a collection of physical, chemical, and microscopic tests performed on urine. Several components in the urine are detected and measured by the tests, including byproducts of normal and abnormal metabolism, cells, cellular fragments, and microorganisms.

The kidneys, the two fist-sized organs located on either side of the spine, produce urine. The kidneys filter wastes from the blood, help water regulation and conserve proteins, electrolytes, and other chemicals that the body can reuse. Urine travels from the kidneys down the ureters to the bladder, then through the urethra and out of the body to eliminate anything not required by the body. Urine is usually yellow and clear; however, due to variable constituents, the urine's color, quantity, concentration, and content will vary slightly each time a person urinates.

Many disorders can be detected early on by examining for substances in the urine that aren't ordinarily present and monitoring abnormal levels of particular substances. Examples are glucose, protein, bilirubin, red blood cells, white blood cells, crystals, and microorganisms. They could be present because of the following reasons:

• The body responds to an elevated level of the substance in the blood by removing the excess through urine.
• Underlying kidney disease.
• A urinary tract infection

Three distinct testing phases make up a complete urinalysis:

A visual evaluation of the color and clarity of the urine.

A chemical examination determines the concentration of urine and tests for various substances present that provide helpful information about health and disease.

Microscopic examination identifies and counts the different types of cells, casts, crystals, and other components found in urine, such as bacteria and mucus.

What is the test used for?

Urinalysis is a test that can diagnose a variety of diseases. It can be used to detect and diagnose conditions like urinary tract infections, kidney diseases, liver problems, diabetes, and other metabolic disorders.

A urinalysis is a set of chemical, microscopic, and visual tests performed to look for cells, cell fragments, and substances like crystals or casts in the urine that are linked to various conditions. It can detect abnormalities that may necessitate further investigation and testing. Protein and glucose often start showing up in the urine before people realize they have a problem.

Urinalysis may be performed in combination with other tests, such as urine albumin, to monitor treatment in people with conditions like kidney disease or diabetes.

Why and when do you need this test?

•  A urinalysis may sometimes be ordered during: 
• A routine wellness check
• A person admitted to the hospital; or will undergo surgery
• When a woman has a pregnancy checkup
• When a person visits a doctor with symptoms of urinary tract infection or another urinary system 

The following are some problem possible signs and symptoms:

• Pain in the abdomen
• Pain in the back
• Blood in the urine 
• Painful or frequent urination

Testing may also be conducted at regular intervals to track the progress of a condition.

What kind of sample is required for the test?

A clean container is used to collect one to two ounces of urine. For accurate results, a sufficient enough sample is necessary. Urine can be collected at any time for a urinalysis. Because it is more concentrated and more likely to detect abnormalities, a first-morning sample may be required in some cases. You may be required to collect a "clean-catch" urine sample sometimes. Before collecting the urine, it is important to clean the genital area. Bacteria and cells from the surrounding skin can contaminate the sample and interfere with test results. Menstrual blood and vaginal fluids can also be sources of contamination in women.

A urine sample will only be helpful for a urinalysis if it is taken to a health care provider's office or laboratory and processed quickly. If the interval between collection and transport will be more than an hour, the urine should be refrigerated or a preservative added.

Do you need to prepare for the test?

Many factors can influence or interfere with the tests that make up a urinalysis. It is important to correctly follow the instructions if a "clean-catch" sample is required. Give your healthcare provider a comprehensive medical history, including any prescription or over-the-counter medications or supplements you're using. If you're a woman, make sure to tell your doctor if you're menstruating.

The collection time is usually not important because this is a general screening test, though a first-morning void may be preferred because it is more concentrated. You may be asked to take a sample at a specified time if your health care professional is looking for a specific finding.

Are there any risks to this test?

Having a urine test carries relatively no risk. 

What do the test results mean?

Color: Urine produced can be of various colors, the most common of which are yellow tones ranging from extremely light or colorless to very dark or amber. A disease process, several medications (e.g., multivitamins can turn urine bright yellow), or eating certain foods can all cause unusual or abnormal urine colors. Some people, for example, may have red urine after eating beets; this is due to the natural pigment in beets and is not a reason for worry. On the other hand, red-colored urine can occur when blood is present in the urine and can be a sign of disease or damage to the urinary system. Another example is urine that is yellow-brown or greenish-brown in color, which could indicate bilirubin in the urine.

Clarity: The clarity of urine refers to how clear it is. Clinical laboratories usually use one of the following terms to describe the clarity of the urine: clear, slightly cloudy, cloudy, or turbid. Urine can be clear or cloudy in "normal" situations. Mucus, sperm and prostatic fluid, skin cells, normal urine crystals, and contaminants such as body lotions and powders are examples of substances that induce cloudiness but are not harmful. Other substances that can cloud urine, such as red blood cells, white blood cells, or bacteria, indicate a medical condition that has to be addressed.

Specific Gravity: The specific gravity of urine is a measurement of its concentration. This test determines the concentration of urine. The amount of substances dissolved in urine is compared to those dissolved in pure water in specific gravity measurements. The specific gravity of urine would be 1.000 if no substances were present (the same as pure water). A urine SG of 1.000 is not feasible because all urine contains certain substances. When a person consumes a lot of water in a short amount of time or has a large intravenous (IV) infusion of fluid, the urine specific gravity can be very near to that of water. Knowing the urine concentration can help health care professionals figure out if the urine samples they're looking at are optimal for detecting a particular substance. A concentrated morning urine specimen, for example, would be the optimum sample if they were looking for minimal levels of protein.

pH: There are "normal" but not "abnormal" urine pH levels, just as there are "normal" but not "abnormal" specific gravity values. The urine is normally slightly acidic, with a pH of around 6. However, it can vary between 4.5-8. The kidneys are responsible for regulating the body's acid-base balance. As a result, any condition that causes the body to create acids or bases, such as acidosis or alkalosis, or the consumption of acidic or basic foods, can directly impact urine pH. When the urine is acidic, some dissolved substances precipitate out to create crystals; when the urine is basic, other substances precipitate out to form crystals. A kidney stone, also known as a "calculus," can develop when crystals build in the urine produced by the kidneys.

Bilirubin: This examines the presence of bilirubin in the urine. Normal, healthy people do not have bilirubin in their urine. It's a waste product made by the liver from the hemoglobin of RBCs that has been broken down and removed from circulation. It becomes a component of bile, a digestive fluid that is released into the intestines. Excess bilirubin can build up in the bloodstream and be removed through urine in some liver diseases, such as biliary obstruction or hepatitis. Bilirubin in the urine is an early sign of liver disease that might arise before clinical symptoms like jaundice appear. The findings of this test will be evaluated with the urobilinogen result. If the test results are positive, the health care provider will likely order more lab tests, such as a liver panel, to help establish a diagnosis.

Urobilinogen: It detects the presence of urobilinogen in the urine. The results are compared to those for bilirubin in the urine. Urobilinogen is found in the urine in low amounts in most people. It is made from bilirubin in the intestine, and a portion of it is absorbed back into the blood. Positive test findings could indicate viral hepatitis, cirrhosis, or liver damage caused by medications or toxic substances, as well as disorders linked to increased RBC destruction (hemolytic anemia). Urine urobilinogen levels that are low or absent in a person who has urine bilirubin and signs of liver disease may indicate hepatic or biliary obstruction.

Protein: Albumin accounts for roughly 60% of total protein in the blood. There will be no protein in the urine or only a small amount of protein in most cases. Proteinuria is a condition in which a person's urine protein level is abnormally high. Proteinuria can occur in healthy people occasionally. Stress, exercise, fever, aspirin therapy, or exposure to cold, for example, might cause temporary or persistent proteinuria in healthy people. Once these conditions have resolved, testing to see if the proteinuria is still present can be done.

If trace amounts of protein are detected, a repeat urinalysis and dipstick protein test may be performed later to evaluate if there is still protein in the urine or if it has decreased back to undetectable levels, depending on the person's signs, symptoms, and medical history.

A 24-hour urine protein test may be utilized as a follow-up test if a large amount of protein is detected on a urinalysis and if the protein persists in repeated tests. The 24-hour urine protein test may be ordered if a healthcare practitioner feels that proteins other than albumin are being released into the urine, as the dipstick only measures albumin.

Glucose: Glucose is not normally found in urine. Glucosuria is a condition that occurs when there is a lot of glucose in the body. It can be caused by one of two things:

1. An abnormally high blood glucose level is found in patients with uncontrolled diabetes.
2. A lower "renal threshold"; when blood glucose levels reach a particular level, the kidneys begin to excrete glucose into the urine, lowering blood glucose levels.
3. Hormonal disorders, liver disease, medications, and pregnancy are other conditions that might induce glucosuria.

Other tests, such as fasting blood glucose, are usually performed when glucosuria occurs to help identify the exact cause.

Ketones: Ketones are generally not present in urine. They're fat metabolism's intermediary products. They are formed when the body's cells do not have access to glucose as an energy source. They occur when a person consumes insufficient carbs (for example, during fasting, famine, or high-protein diets) or when the body's ability to use carbohydrates is impaired. When carbs are unavailable, the body converts fat to provide its energy to function. Ketonuria can also be caused by strenuous exercise, exposure to cold, prolonged vomiting, and various digestive system diseases.

Ketones in the urine can potentially be an early sign of insulin deficiency in people with diabetes. A person with diabetes who does not have enough insulin cannot process glucose and instead metabolize fat. This can lead to a build-up of ketones in the blood, resulting in ketosis and eventually ketoacidosis, a kind of metabolic acidosis. The kidneys release excess ketones and glucose into the urine to remove them from the body. Diabetic ketoacidosis (DKA) is a medical emergency that occurs most frequently in people with uncontrolled type 1 diabetes.

Blood and Myoglobin: The purpose of this test is to detect hemoglobin in the urine (hemoglobinuria). Hemoglobin is a protein present inside red blood cells that transports oxygen (RBCs). Its presence in the urine indicates the presence of blood (known as hematuria).In most cases, a small number of RBCs are detected in urine, resulting in a "negative" chemical test. A "positive" chemical test result is defined as an increased amount of hemoglobin and an increased number of RBCs. To assess whether RBCs are present in the urine, the results of this test are usually combined with those from a microscopic examination of the urine. With no RBCs present, a positive result on this test could suggest the presence of hemoglobin in the urine (which can happen when RBCs break apart) or myoglobin from muscle injury. Blood in the urine is not a common occurrence, but it is not necessarily a cause for concern. Your healthcare provider will investigate the situation further to establish the source and underlying cause of the blood and may order more testing to see if the blood is persistent.

Leukocyte esterase: Most white blood cells contain the enzyme leukocyte esterase. In most cases, a few white blood cells are found in urine, resulting in a negative chemical test result. This screening test will turn positive when the quantity of WBCs in urine dramatically increases. The results of this test will be evaluated against a microscopic analysis of the urine for WBCs. When this test is positive and the WBC count in urine is high, it could mean that the urinary tract or kidneys are inflamed. A bacterial urinary tract infection (UTI), such as a bladder or kidney infection, is the most common cause of WBCs in urine (leukocyturia). Bacteria and RBCs can also be seen in the microscopic examination, in addition to WBCs.

Nitrite: This test detects nitrite and is based on the fact that many bacteria can convert nitrate (a naturally occurring substance in urine) to nitrite. Bacteria and nitrates are normally absent from the urinary tract and urine. Bacteria can cause a urinary tract infection when they enter the urinary tract. A positive nitrite test can indicate a urinary tract infection. However, because not all bacteria can convert nitrate to nitrite, a UTI can occur even if a nitrite test is negative. The results of this test and the leukocyte esterase and microscopic examination will be considered.

Ascorbic Acid: People who take vitamin C or multivitamins may occasionally have high levels of ascorbic acid in their urine. A laboratorian may test the sample for ascorbic acid (vitamin C) if this is suspected because it has been known to interfere with the accuracy of several chemical test strip findings, leading them to be inaccurately low or falsely negative. Urine dipstick tests for glucose, blood, bilirubin, nitrite, and leukocyte esterase are among the tests that may be affected.

Microscopic Examination

Red Blood Cells: In most cases, a few RBCs can be seen in urine sediment (0-5 RBCs per high power field, HPF). There is blood in the urine if a chemical test for hemoglobin is positive and the number of RBCs visible under a microscope increases. This test, however, cannot be used to identify the source of the blood. For example, a bleed in the urinary tract cannot distinguish urine contaminated with hemorrhoids or vaginal bleeding blood. This is why it is critical to collect a urine specimen properly and for women to inform their healthcare provider if they are menstruating when a urine test is requested.

Blood in the urine is not a common occurrence, but it is not necessarily a cause for concern. Hematuria is a sign or indicator that encourages a health care provider to look into the situation further to determine the blood source. A health care practitioner will assess an individual's medical history, physical examination, and accompanying signs and symptoms as part of the investigation. Other urine and blood test may be performed to determine the source. Some of the underlying causes of hematuria are benign, temporary conditions that produce no long-term harm and go away with little or no treatment.

A urinary tract infection, which can be easily treated with antibiotics, may be the cause of blood in the urine combined with white blood cells and bacteria. Some causes of hematuria, on the other hand, may indicate a serious disease or a long-term condition that requires treatment and monitoring.

White Blood Cells: In most cases, the number of WBCs in urine sediment is low (0-5 WBCs per high power field, HPF). WBCs from vaginal secretions, for example, can be a contaminant.

A higher number of WBCs in the urine under a microscope, as well as a positive leukocyte esterase test, could indicate an infection or inflammation in the urinary tract. They indicate a urinary tract infection if bacteria also accompany them.

Epithelial Cells: Epithelial cells are commonly reported as "few," "moderate," or "many" (LPF). Normally, a few epithelial cells can be identified in the urine sediment of both men and women. An increased number of epithelial cells are seen in urinary tract diseases such as infections, inflammation, and malignancies. Identifying the kind of cells present can sometimes help diagnose certain conditions. Epithelial cells with large amounts of hemosiderin (broken-down hemoglobin) may indicate that red blood cells or hemoglobin were present in the urine recently, even if there are none presently.

Bacteria Yeast and Parasites: The urinary tract is sterile in healthy humans. If the urine sample is taken as a "clean-catch" sample, no microbes will be visible in the urine sediment under a microscope. To prevent bacteria that ordinarily live on the skin or in vaginal secretions from contaminating the urine sample, special precautions must be followed during specimen collection, especially in women.

Bacteria from the skin can enter the urinary tract through the urethra and spread to the bladder, resulting in a urinary tract infection (UTI). If left untreated, the infection can spread to the kidneys, resulting in kidney infection (pyelonephritis). If a person has an uncomplicated lower urinary tract infection, they may not need a urine culture to be treated. A urine culture and susceptibility testing may be conducted to help guide treatment if the person has had repeated UTIs, has a suspected complicated infection, or is hospitalized.

Yeast can be found in the urine of women (and very rarely in men). Because the urine has been contaminated with vaginal secretions during collection, they are most commonly found in women who have a vaginal yeast infection. If yeast is found in the urine, the person may be diagnosed with a yeast infection and treated accordingly.

The parasite Trichomonas vaginalis can be discovered in the urine of both men and women. T. vaginalis infects the vaginal canal in the same way that yeast does, and their presence in urine results from contamination during sample collection. Trichomonas tests for a vaginal infection may be performed if these are discovered during a urinalysis.

Casts: Casts are cylindrical particles that form from coagulated protein released by kidney cells and are sometimes found in urine. They are formed in the tubules, which are long, thin, hollow tubes in the kidneys that normally take the shape of the tubule (hence the name). They have the shape of a "hot dog" under the microscope, and they are practically clear in healthy persons. A "hyaline" cast is the name for this sort of cast. Healthy people may have a few (0–5) hyaline casts per low-power field in normal circumstances (LPF). More hyaline casts may be found after strenuous exercise.

Other types of casts have been linked to various kidney diseases, and the type of casts found in the urine can help identify the disorder affecting the kidney. A kidney problem is indicated by cellular casts, such as red blood cells and white blood cell casts. Granular casts, fatty casts, and waxy casts are examples of other types of casts. Cells or other substances can become trapped in the protein as the cast forms if kidney disease occurs. The cast is then identified by the substances contained inside it, such as a red blood cell cast or a white blood cell cast.

Crystals: Many dissolved substances (solutes) - waste chemicals that the body must eliminate – can be found in urine. If the following conditions exist in the urine, these solutes can form crystals:

1. The pH of the urine becomes increasingly acidic or basic; 
2. The concentration of dissolved substances increases; and 
3. The temperature of the urine promotes their production.

The shape, color, and pH of the urine help identify crystals. They can be amorphous (tiny sand-like particles) or have distinct forms, such as needle-like. The following are some examples of crystals found in the urine of healthy people:

• Amorphous urates
• Crystallised uric acid
• Calcium oxalates
• Amorphous phosphates 

The crystals are considered "abnormal" if they come from substances that aren't ordinarily found in the urine. Abnormal crystals could indicate a metabolic process that isn't working correctly. Here are a few examples:

• Cystine 
• Tyrosine
• Leucine
• Calcium carbonate

As urine is produced, normal or abnormal crystals can form within the kidneys, which can then combine to form kidney "stones" or calculi. These stones can lodge in the kidney or the ureters, which carry urine from the kidney to the bladder, causing severe pain.

Related tests: Urine Culture, Urine Protein, and Urine Protein to Creatinine Ratio, Creatinine serum, Urine Albumin and Albumin to Creatinine Ratio, Kidney Stone Testing, Renal Panel test, Bilirubin total test