Urinalysis Flashcards
What is urinalysis?
A test that determines the content of the urine
What is the function of a urinalysis?
- Because urine removes toxins and excess liquids from the body, its contents can provide vital health information.
- Urinalysis can be used to detect some types of disease, particularly in the case of metabolic disorders and kidney disease.
- Urinalysis can also be used to uncover evidence of drug abuse.
What are the 3 components of urinalysis?
- Gross assessment of the urine (Macroscopic Examination)
- Urine dipstick analysis (Chemical Analysis)
- Microscopic examination of the urinary sediment (Microscopic Examination)
Describe specimen collection?
- The specimen should be collected into a clean, dry container.
- Patients should be asked to clean the external genitalia and provide a midstream specimen for analysis.
- In patients with indwelling urinary catheters, a sample should be obtained directly from the catheter tubing, rather than from the urometer or drainage bag.
- The specimen should be examined at room temperature within two hours of retrieval. If this is not feasible, the sample should be refrigerated at 2 to 8°C and then re-warmed to room temperature prior to assessment.
Describe gross assessment of the urine?
Looking at the physical properties of the urine:
1. Color
- Normal urine is clear and light yellow in color
- Urine turbidity and color may be altered in a number of settings
2. Clarity (transparency)
- Normal urine should be clear
- Abnormal urine can be: hazy, cloudy, or turbid
Describe urine dipstick analysis?
• The urine dipstick provides a rapid semi quantitative assessment of urinary characteristics on a series of colorimetric pads embedded on a test strip.
• Most urine dipsticks permit the analysis of the following core parameters: specific gravity, pH, heme, leukocyte esterase, nitrite, albumin, and glucose.
• Some dipsticks include test pads for additional parameters including urobilinogen and ketones, although these are generally not used in the diagnosis of kidney disease.
• Users should be familiar with the specific characteristics of the reagent strips they are using and adhere to manufacturer instructions regarding the amount of urine required and the time that needs to elapse before interpreting the color on any given test pad.
pH test of chemical analysis?
pH of normal urine?
Test measures if urine is acidic, basic or neutral
- Normal urine ranges from 4.6 to 8.0
- Most often used clinically in patients with metabolic acidosis
Specific gravity test of chemical analysis?
Test measures the concentration of particles in the urine and evaluates the body’s water balance.
- The more concentrated the urine, the higher the urine specific gravity.
- The most common increase in urine specific gravity is the result of dehydration.
- Normal urine ranges between 1.002 to 1.028
Ketone test of chemical analysis?
Test measures the presence or absence of ketones : the endpoint of rapid or excessive fat breakdown, in the urine.
- Normal urine does not contain ketones
- indicator for Type 1 diabetes
Protein test of chemical analysis?
Normal protein levels in urine?
Normal urine levels of proteins (called albumin) are very small, usually approximately 0 to 8 mg/dl.
Glucose test of chemical analysis?
The test measures the amount of sugar in a urine sample
- Normal urine does not contain glucose.
Leukocyte esterase test of chemical analysis?
Leukocyte esterase released by lysed neutrophils and macrophages is a marker for the presence of white blood cells (WBCs)
- However, a concentrated urine may impede cell lysis and therefore produce a false-negative result
- Proteinuria and glucosuria may also lead to a false-negative test for leukocyte esterase
Nitrite test of chemical analysis?
Indication?
Conversion of nitrate to nitrite indicates the presence of UTI causing bacteria
- elaborate the enzyme nitrate reductase, which converts urinary nitrate to nitrite
- nitrite-positive urine may indicate underlying bacteriuria
