The purpose of a urine test is to check for various components of urine, which is a waste product produced by the kidneys. What does a urine test show? With the help of the urine test the information about the health and different illnesses of a person can be found. Urine is formed of hundreds of different body’s waste substances. What you drink and eat, how much exercise you do and how well the functioning of your kidneys, all of this can affect the composition of your urine.
Why Is a Urine Test Done?
A urine test is usually done:
To check for the infection and disease of the urinary tract. Some of the symptoms of a urinary tract infection are pain while passing urine, bad-smelling or colored urine, difficulty in urinating, pain in the lower abdominal region, fever or blood in urine.
To monitor the treatment of diseases such as kidney stones, diabetes, hypertension, urinary tract infection, some liver or kidney diseases.
It may be done as a part of a regular physical exam.
What Does a Urine Test Show?
Color: The color of the urine is pale to dark yellow normally. The color is affected by many things such as diet, fluid balance, diseases and medicines. For instance, urine can be turned bright yellow by vitamin B supplements. Dehydration may cause the color to be dark yellow. Blood in urine may cause the color to be red. Uncontrolled diabetes or long-term kidney disease may cause the urine to be of no color.
Clarity: A normal urine specimen is clear. Urine can look cloudy due to presence of pus (WBC), crystals, bacteria, yeast, sperm, blood (RBC), mucus or infection by a parasite such as trichomoniasis.
Odor: The urine does not have a very strong odor but a slightly aromatic or nutty odor. Odor of urine may be changed by some diseases; for instance, starvation or diabetes can lead to a sweet, fruity odor or smell of urine. Certain foods such as asparagus, antibiotics such as penicillin, and vitamins can lead to a different odor of urine. A bad odor may be caused by a urinary tract infection. In maple syrup urine disease, urine may smell like maple syrup.
Specific gravity: Specific gravity of normal urine specimen is between 1.005 and 1.030. Specific gravity tells the balance between water and different substances in urine and shows whether the kidneys are properly functioning or not. A very high specific gravity implies that the urine is very concentrated, which may occur due to drinking less fluids, excessive loss of fluids such as in diarrhea, vomiting or sweating, or presence of substances such as protein or sugar in urine. A very low specific gravity implies that the urine is very dilute, which may occur as a result of drinking large quantities of fluids, use of diuretics or severe kidney disease.
pH: What does a urine test show? The pH of urine tells how alkaline or acidic it is. The average pH of normal urine is about 4.6-8.0. Certain foods such as citrus fruits and medicines such as antacids can affect the pH of urine. The pH can become alkaline due to severe vomiting, UTI, kidney disease and asthma. The value can become acidic due to emphysema, aspirin overdose, uncontrolled diabetes, dehydration, starvation, and drinking too much alcohol.
Protein: Normally protein is not present in the urine. Protein is found in the urine in the following situations: fever, pregnancy (Preeclampsia), strenuous exercises, and some diseases such as kidney disease, high blood pressure, cancer, diabetes, systemic lupus erythematosus, heart failure, leukemia.
Glucose: Normally, glucose is not present in the urine or a minimum amount is present. Too much glucose is present in urine in cases of uncontrolled diabetes, liver damage, adrenal gland problem, brain injury, and some types of kidney diseases. Glucose may be found in the urine of healthy pregnant females.
Nitrites: Bacteria causing (UTI) urinary tract infection secrete an enzyme, which leads to the conversion of nitrates present in the urine to nitrites. Hence, nitrite present in the urine is an indication of a UTI.
WBC esterase (Leukocyte esterase): Leukocyte esterase indicates that WBCs are present in the urine, which is an indication of a UTI.
Ketones: When fats are used for producing energy, ketones are formed, which are passed in the urine. When large quantities of ketones are present in the urine, it indicates a very serious condition, referred to as diabetic ketoacidosis. Ketones are also present during starvation, or severe vomiting or when a person eats a diet having low amount of starches and sugars or in eating disorders such as bulimia or anorexia nervosa.
Microscopic analysis: Microscopic analysis is also done to answer the question what does a urine test show? During this test the urine is centrifuged so that the sediments settle at the bottom. These sediments are then placed on a slide and seen under a microscope. The slide may show:
1. White or red blood cells: Normal urine does not contain blood cells. Injury, disease, or inflammation of the kidney may lead to presence of blood in urine. Blood may also be present due to doing strenuous exercise, or due to kidney stones, systemic lupus erythematosus or bladder or kidney tumor. White blood cells may show infection or disease of kidney, or inflammation under the foreskin of the penis or in the vagina.
2. Casts: Casts are plugs of materials that are formed in the tiny tubes of the kidneys in some forms of kidney disease. Presence of casts in urine can imply various illnesses depending upon the type of the cast such as damage or inflammation of the kidneys, metal poisoning, poor blood supply to the kidneys, bacterial infection or heart failure.
3. Crystals: Very few crystals are present in the urine of healthy people. Presence of specific types of crystals or a large number of crystals indicate presence of kidney stones or problems with metabolism.
4. Bacteria, parasites or yeast cells: Normally none of them are present in the urine. When they are present, it indicates an infection.
5. Squamous cells: Presence of squamous cells indicates that the sample is impure.