1. Chapter 42
Urinalysis

2. Urine Formation
Urine forms in kidneys and leaves body through urinary tract system
The urinary system >>
[FIGURE 42-1]

3. Urine Formation Kidney regulates fluid outside cells of body
Maintains homeostasis
Two kidneys, one on each side of body; 11 to 12 cm long and 5 to 6 cm wide
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4. Urine Formation Filtration
Glomerulus filters waste products, salts, excess fluid from blood
Tubule concentrates filtered material
Nephron
Combination of glomerulus and tubule
One million nephrons in each kidney

5. Urine Formation Filtration Substances filtered out from body Water
Ammonia
Electrolytes
Glucose
Amino acids
Creatinine
Urea

6. Urine Formation Reabsorption
About 180 liters of filtrate produced daily
Only 1–2 liters of urine eliminated
Much filtrate reabsorbed into body
Blood cells and most proteins stay in blood
Concentration of glucose in blood below 180 mg/dl will be reabsorbed
Glucose is threshold substance

7. Urine Formation Secretion
Substances not already filtered secreted into urine through distal convoluted tubule
Hydrogen and ammonium ions may be secreted into urine in exchange of sodium

8. Urine Composition
After passing through kidney, urine 96% water and 4% dissolved substances (urea, salt, sulfates, phosphates)
(See Table 42-1: Normal and Abnormal Substances in Urine)

9. Urine Composition Abnormal constituents of urine
Red and white blood cells
Fat
Glucose
Casts
Bile
Acetone
Hemoglobin

10. Urine Composition Changes in urine production
Amount of urine excreted can increase or decrease
Urine color can change
Urine appearance can vary

11. Urine Composition Changes in urine production Urine odor can change
Cells can be present in urine
Chemical constituents in urine can change
Urine concentration (specific gravity) may vary

12. Safety Standard Precautions Transmission-Based Precautions
Biohazard precautions

13. Quality Control Regulatory agencies Quality control (QC) programs
Written testing protocols
Maintained testing records
Recalibration of instruments

14. Quality Control
Documentation of daily control testing must be kept at least 3 years
Commercially available urine control samples
Run positive and negative controls each day on all tests

15. CLIA ’88 Appropriate training in methodology of test being performed
Understanding of urine testing QC procedures
Proficiency in use of instrumentation; being able to troubleshoot problems

16. CLIA ’88 Knowledge of stability and proper storage of reagents
Awareness of factors that influence test results
Knowledge of how to verify test results
CLIA categorizes microscopic exam of urine as a PPMP

17. Urine Containers Types Nonsterile containers for random specimens
Sterile containers for cultures
24-hour collection containers with added preservatives
[FIGURE 42-3]

18. Urine Containers
Before handing urine specimen cup to patient, label with patient’s name, date, time
Follow protocol of your facility
Use permanent marker
Always label cup, not lid

19. Urine Collection Urine specimen types Random (spot) specimen
Obtained at any time
Most common
Patient should be able to provide specimen within 15 to 20 minutes of drinking several cups of water

20. Urine Collection Urine specimen types First morning void specimen
Most concentrated specimen
Higher acid pH
Preferred, but seldom ordered

21. Urine Collection Urine specimen types Fasting/timed specimens
Provider wants to measure substance without interference from food intake
Length of fast varies
Give patient written directions
Use regular urinalysis container

22. Urine Collection Urine specimen types 24-hour specimen
Circadian rhythm and intake of food and water determine concentration of substances during 24-hour period
Requested when quantitative tests for different substances desired
Expressed in units per 24 hours
Use of preservatives and refrigeration
Sometimes use 2-hour or 12-hour collection instead

23. Urine Collection Collection methods Clean-catch midstream
Cleanse genital area before collection
Patient should begin to urinate into toilet
Pulls cup into urine stream and collects sample
Removes cup from stream and voids rest of urine into toilet

24. Urine Collection Collection methods Catheterized
Insertion of sterile tube into bladder through urethra
Completely sterile specimen
Only performed under provider’s order and only by health care professionals who have been trained
Can cause infection if not done correctly

25. Urine Collection Collection methods Culture and sensitivity of urine
MA responsible for preparing sample for transport
Urine Culture and Sensitivity Transport kit
(See Procedure 42-6: Utilizing a Urine Transport System for C&S)

26. Examination of Urine Fresh state, preferably still warm
Urinalysis performed as soon as possible, preferably within 2 hours

27. Examination of Urine Physical examination of urine
Assess volume of urine specimen, making sure amount sufficient for testing
Note any unusual urine odor
Measure specific gravity of specimen
(See Procedure 42-1: Assessing Urine Volume, Color, and Clarity (Physical Urinalysis))
(See Procedure 42-2: Using the Refractometer to Measure Specific Gravity (Physical Urinalysis Continued))

28. Examination of Urine Physical examination of urine
[FIGURE 42-4]
Physical examination of urine
Observe and record color, appearance, transparency

29. Examination of Urine Physical examination of urine Specimen volume
First step in performing urinalysis
Enough urine to fill test tube with 10 mL of urine
Urine color
Ranging from pale yellow to dark yellow or amber
Result of concentration of urine
Diet and certain drugs can add color
(See Table 42-2: Urine Colors and Possible Causes)

30. Examination of Urine Physical examination of urine Urine transparency
Clear, cloudy, hazy, turbid (opaque)
Urine odor
Odors should not be disregarded
Sweet (diabetic ketoacidosis)
Foul (bacteria)

31. Examination of Urine Physical examination of urine
Urine specific gravity
Ratio of weight of given volume of substance to weight of same volume of distilled water at same temperature
Concentrations of solids in urine
Tested by using test strip, urinometer, refractometer

32. Examination of Urine Physical examination of urine Urinometer
Measures specific gravity
Calibrated, floating device
Least accurate method and most difficult

33. Examination of Urine Refractometer
Most common tool for determining specific gravity of liquids
Measures refractive index of urine
Reads about less than that of true specific gravity
Needs 1 drop of urine
Easy to use and reliable
[FIGURE 42-5A]

34. Examination of Urine Physical examination of urine Reagent test strips
Available through medical laboratory supply companies
Look for SG in name
More tests on reagent test strips, more expensive the product

35. Examination of Urine Chemical examination of urine
Use of reagent strips with color-coded chart
Chemical testing available on urine reagent test strips
[FIGURE 42-16C]

36. Examination of Urine Chemical examination of urine
Specific reagent test strips
Glucose pH
Protein
Ketones
Bilirubin

37. Examination of Urine Chemical examination of urine
Specific reagent test strips
Blood
Urobilinogen
Nitrite
Leukocytes
Specific gravity
(See Table 42-3: Chemical Testing Available on Urine Reagent Test Strips)

38. Examination of Urine Chemical examination of urine
Reagent test strip quality control
Automated urine analyzers >>
[FIGURE 42-7E]
(See Procedure 42-5: Performing a Complete Urinalysis)
(See Table 42-4: Reagent Strip Sensitivity)

39. Examination of Urine Microscopic examination of urine sediment
Considered as PPMP
Sediment at bottom of centrifuge tube
Helps determine kidney disease, disorders of urinary tract, systemic disease
Freshly voided urine
Use of urine color atlas
Use of urine stains

40. Examination of Urine Microscopic examination of urine sediment
Sediment components
Centrifuge 10–15 mL of urine
Pour off supernatant urine
Resuspend sediment by tapping
Put drop of sediment on slide

41. Examination of Urine
Sedi-Stain® example of stain used in laboratories >>
[FIGURE 42-8]

42. Abnormal Urine Sediment Cells and Microorganisms
RBC
WBC
Renal tubular epithelial cells
Bacteria
Yeast
Parasites
Sperm
Artifacts
Squamous epithelial cells

43. Examination of Urine Crystals in urine sediment
Insignificant part of urinary sediment
Calcium phosphate, triple phosphate, calcium oxalate, amorphous phosphates and urates, calcium carbonate
Form as urine specimens stand
May indicate disease: uric acid, cystine, sulfa drug crystals

44. Examination of Urine Casts in urine sediment
Important to see and identify
Formed when protein accumulates and precipitates in kidney tubules
Appearance of casts
Hyaline cast most common kind seen
Granular casts and cellular casts also seen
Takes experienced eye to identify
(See Procedure 42-4: Preparing Slide for Microscopic Examination of Urine Sediment)
(See Procedure 42-5: Performing a Complete Urinalysis)

45. Urinalysis Report
Include patient’s name, type of specimen, collection method, ordering provider, MA name, date and time of collection, date and time of testing, findings
[FIGURE 42-13]

46. Drug Screening Becoming more common for employment
Test itself is CLIA waived, but detailed protocols must be followed
Chain of custody