The Medical Urinalysis Procedure: How It Is Performed and What the Values Mean

The Medical Urinalysis Procedure: How It Is Performed and What the Values Mean
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Overview

A urinalysis is a simple test that can help physicians access a person’s overall health, detect medical disorders, and monitor conditions through evaluation of the urine. This test can basically check for urinary tract infections, kidney disorders, diabetes, and liver problems. The most important part of this test is that the procedure for doing a medical urinalysis test is done correctly from the start. For a routine urinalysis, you can eat or drink normally before voiding.

Specimen Collection

A urine collection must be done properly to avoid inaccurate results. A urine specimen should be done fresh in order to obtain the most accurate results. If a specimen must be kept for a period of time, then it should be refrigerated. Patients should be given a wide-mouthed sterile cup to catch the urine. A clean-catch urine specimen is taken in this order:

  1. Clean the entire vulvar area in women from front to back and the genitals in men with a disinfectant towelette. Sometimes physicians will also recommend using a Betadine swab along with the towelette.
  2. The patient should begin to void into the toilet and then catch urine in the sterile cup container during midstream voiding of at least 1-2 ounces of urine. Finish voiding in the toilet.
  3. The patient can screw on the container cap (if given) or leave for the medical assistant or nurse to complete.

The Processing of a Urine Specimen

First the urine is viewed to see the color and if it is clear or cloudy. Cloudiness or an unusual odor could mean an infection. Blood in the urine will cast a reddish or brown appearance. Next the urine is dipped with a special chemical strip into the urine. Each strip has pads that will change colors according to what is present in the urine specimen. Here are the values that are checked during a routine urinalysis.

  • pH (acidity or alkalinity) - normal urine has a pH range from 4.5 to 7.5 which goes from slightly acid to neutral. This test can only be done with fresh urine. Abnormal pH can indicate a urinary tract or kidney infection.
  • Specific gravity measures the dilution or concentration of the urine. If the urine is highly concentrated, it could mean that the patient is dehydrated.
  • Protein (Albumin) is not normally seen in urine. It may be seen if the urine has not been properly collected or if women have a vaginal discharge (giving misleading results). True proteinuria (high
  • protein in the urine) could mean a renal disease and should be investigated further by a physician.
  • Glucose in the urine is not normal and warrants further investigation. It could be from a patient with diabetes mellitus, or sometimes even in a healthy woman during pregnancy.
  • Ketone bodies found in urine are also abnormal. Ketones are also referred to as ‘acetone’ on lab sheets. Ketones in the urine can be associated with a person with diabetic acidosis or in cases of severe starvation or body wasting (cachexia).
  • Bilirubiin (Bile) may appear in urine when there is some obstruction of the extrahepatic biliary system. It can also appear in patients who have liver damage or hepatitis. Sometimes a urinalysis will catch this disorder before a person becomes jaundiced.
  • Occult Blood is another word for hidden blood, which cannot been seen with the naked eye.
  • Nitrites or Leukocytes are a product of white bloods cells which are sure signs of a urinary tract infection.

Some physicians use only the dipstick method for doing a urinalysis and others go further to microscopically look at urine on a slide. Here is what physicians look for:

  • Red blood cells which are not normal in the urine, but can be a result from menstrual blood or some tissue damage during a catheterization process. Further examination is needed to rule out a kidney disorder.
  • White blood cells, sometime call ‘pus cells’ are usually found in voided specimens, especially from women. It is normal to have a small amount up to 5 cells, but an excess needs to be evaluated further for infection.
  • Epithelial cells can be found in urine. Three types are renal cells, transitional cells, and squamous cells. Each type cell plays an important role in diagnosing a disorder within organs such as kidneys, bladder, ureters, urethra, and vagina.
  • Casts (or urinary tubules) are highly diagnostic cells seen in urine with a pH of 6.0 or less and with a high salt concentration. Casts are named according to what is seen in them, such as pus, blood, or granular (crystals).
  • Crystals are seen in urinary sediment and are classed by the pH of the urine. They are noted in either acidic or alkaline urine and noted as they may be a cause of renal calculi (stones).

Urine specimens are sometimes sent out to labs to run cultures to see what type bacteria may be growing if pus is seen. This information is helpful to physicians in order to prescribe the right type of antibiotic that is specific to the infection. Being meticulous in the procedure for doing a medical urinalysis test is of utmost importance for an accurate diagnosis.

References

The Medical Office Assistant: Administrative and Clinical; 5th Edition by Portia M. Frederick, CMA-AC & Mary E. Kinn, CPS. CMA-A [W.B. Saunders Co. 1981]

Urinalysis” Mayo Clinic website

Photo Credit

Urine testing strips - https://www.dreamstime.com/laboratory-test-stripe-image14016167