14 August, 2017
Components of Urine Analysis
Years ago, physicians would taste your urine to check for diabetes. Of course, that is no longer done, but an analysis of your urine is still important. It is not only vital if you have kidney disease, the organ that makes urine, or if you suffer from any disease that involves your urinary tract, but it can also be useful in the detection and progression of certain other diseases as well; diabetes mellitus for one. A complete urinalysis involves checking for the appearance of your urine, its specific gravity, odor, pH, glucose, ketones, protein, blood cells, casts, nitrite and leukocyte esterase.
Your urine is looked at to determine both its color and what is referred to as its turbidity. Normal urine should have a yellow, straw or amber color. It should not have a red or reddish-brown color. If it does, this could be due to hemoglobin, from your red blood cells; myoglobin, from your muscle cells; certain medications; or food dyes. Is your urine cloudy or foamy? This is what is meant by turbidity. Your urine could be foamy if there is a lot of protein in your urine, for example.
This is a way for your physician to determine whether your kidneys are functioning well enough to be able to properly concentrate your urine. If your specific gravity is too high, your urine has a high osmolality; meaning it is very concentrated. This can happen if you are dehydrated, for instance, because the capillaries in your kidneys will reabsorb your water, so your body can hold onto it. And this will result in a concentrated urine.
Urine will only have a very distinct smell in the case of specific rare diseases; such as when a child has a disease called maple syrup urine disease, where the urine actually smells like maple syrup because of a genetic inability to process certain amino acids.
Your urine should normally be within a specific pH range. Certain bacteria that cause urinary tract infections can raise your urine pH level. Diabetes, on the other hand, is one example of why it could be low.
If the dipstick detects glucose in your urine, this will usually mean you have diabetes mellitus. (If this is the case, your physician will conduct other tests to confirm it.) Note that the dipstick checks for glucose, and not for other sugars. Thus, the urine of newborn babies is checked for the existence of other types of sugar, like fructose or galactose, by other means.
You will only have substances called ketones in your urine if you are in diabetic ketoacidosis (DKA), which is a life-threatening condition, or if you are suffering from starvation.
You should have only a small amount of protein in your urine. And the regular urinalysis only checks for the albumin protein. If you are diabetic and you have high levels of albumin in your urine, that is a sign of kidney disease.
You should not have any red blood cells in your urine sample. If you do, this could be due to damage at any point along your urinary tract; that is, damage in your kidneys, from kidney stones or from a bladder infection. White blood cells in the urine mean those cells are fighting against a urinary tract infection. Epithelial cells are normal, but an increased amount of them means you have damaged kidney tubules, or a kidney condition that is associated with excess protein in your urine.
These are formed in your kidney tubules and are made from protein, blood cells and debris. Red blood cell casts usually mean damage to your kidney capillaries or tubules. White blood cell casts are usually indicative of renal inflammation. Granular casts mean necrosis of your kidney tubules (damage from lack of oxygen), and waxy casts occur during kidney failure.
You should not have any nitrites in your urine sample. If you do, then you have bacteria in your urinary tract, as specific bacteria make nitrites.
This is an enzyme that is released by white blood cells. If this is in your urine, then you most likely have white blood cells fighting a bacterial urinary tract infection.
- “Current Medical Diagnosis and Treatment 2009”; Stephen McPhee, M.D., Maxine Papadakis, M.D.; 2009
- “Introduction to Clinical Medicine”; Roger Macklis, M.D., Michael Mendelsohn, M.D., Gilbert Mudge, Jr., M.D.; 1994
- “WebPath: Urinalysis.”
- Vonschonertagen/iStock/Getty Images