1. Chapter 30
Urinalysis

2. Urine Formation Urine forms in kidneys and leaves body through urethra
The urinary system >>

3. Urine Formation How body excretes water and gets rid of waste
Waste can become toxic if not removed
Two kidneys eliminate soluble waste products of metabolism
Click here for an animation

4. Urine Formation Filtration
Glomerulus filters waste products, salts, and 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

6. Urine Formation Filtration Substances filtered out from body
Amino acids
Creatinine
Urea
Diabetes diagnosis
Routine urinalysis testing

7. 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 a threshold substance

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

9. Urine Composition
After passing through kidney, urine is 96% water and 4% dissolved substances (urea, salt, sulfates, phosphates)

10. Urine Composition Abnormal constituents of urine WBC Fat Glucose Casts
Bile
Hemoglobin and RBC

11. Urine Composition Changes in urine production
Amount of urine excreted can rise or fall
Urine color can change
Urine appearance can vary

12. 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

13. Safety Standard precautions Transmission-based precautions
Biohazard precautions
Proper disposal of urine

14. Quality Control Regulatory agencies Written testing protocols
Maintained testing records
Recalibration of instruments

15. 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

16. CLIA 88 Appropriate training in methodology of test being performed
Understanding of urine testing quality control procedures
Proficiency in the use of instrumentation; being able to troubleshoot problems

17. 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 as a PPMP

18. Urine Containers Types Nonsterile containers for cultures
24 hour collection containers with added preservatives

19. Urine Containers Label container immediately after specimen collection
Patient’s name, age, gender, identifying number
Date and time of collection
Physician’s name
Label the cup, not the lid

20. Urine Collection
Giving patient instructions

21. Urine Collection
Click to play the video

22. Urine Collection Urine specimen types Random (spot) specimen
Obtained at any time
Most common
If concentrated specimen preferred, first specimen of day is most concentrated

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

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

25. Urine Collection Urine specimen types Catheterized specimen
Insert sterile tube directly into bladder through urethra
Not contaminated
Can cause infection if not done correctly
Use only when other methods are contraindicated or show repeated positive testing for bacteria

26. Urine Collection Collection methods Random collection
Clean-catch method; midstream collection
Catheterized

27. Examination of Urine Best when fresh, even still warm
Test within 30 minutes, or refrigerate

28. Routine Urinalysis Procedure
Physical examination of urine
Assess volume of urine specimen, making sure specimen is sufficient for testing
Note any unusual urine odor
Measure specific gravity of specimen

29. Routine Urinalysis Procedure
Physical examination of urine
Observe and record color and transparency of specimen

30. Measuring Specific Gravity
Urinometer
Measures specific gravity
Reading the meniscus
Take temperature of urine into account

31. Measuring Specific Gravity
Refractometer
Most common tool for measuring specific gravity of liquids
Measures refractive index of urine
Reads about below that of true specific gravity
Needs 1 drop of urine
Easy to use but more expensive

32. Routine Urinalysis Procedure
Chemical examination of urine
Use of multistix reagent strips with color-coded chart
Chemical testing available on urine reagent test strips
See Table 42-3

33. Routine Urinalysis Procedure
Chemical examination of urine
Reagent test strip quality control
Automated urine analyzers >>

34. Routine Urinalysis Procedure
Microscopic examination of urine sediment
Classified as PPMP
Sediment is forced to the bottom of centrifuged tube
Helps determine kidney disease, disorders of urinary tract, and systemic disease
Need fresh urine
Use of urine color atlas
Use of urine stains

35. Preparing for Microscopic Examination
Centrifuge 10–15 mL of urine
Pour off supernatant urine
Resuspend sediment by tapping
Stain (optional) >>
Put drop of sediment on slide

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

37. Crystals in Urine Sediment
Require little attention
Form as urine specimens stand
Uric acid, cystine, and sulfa drug crystals can indicate disease states

38. Casts in Urine Sediment
Important to note
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 an experienced eye to identify

39. 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

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