I.
Physical Examination of Urine Activity Handout
Color
A. Normal color: different shades of yellow (but can range from colorless to amber)

1. Color variations (colorless, amber, orange, red, green, blue, brown, black) can be due to: a. b. c. d. e.

2. The main pigment responsible for normal urine color is called
Briefly explain what this pigment is:

3. Because production and excretion of this pigment is constant, the intensity of urine color can be a crude indicator of: a. b.
Dark yellow color indicates:
1)
2)
Pale yellow or colorless urine indicates:

4. Two additional urinary constituents also contribute to urine color. List them and indicate the pigment color: a. b.

5. Why is it recommended all laboratory personnel use the same terminology when describing urine color?
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
B. Abnormal color and possible causes: (This list is not inclusive; refer to tables on page 103 and 105 in textbook)
1. Bright yellow: most often due to multivitamins
2. Amber, dark amber:
Orange:
4.
3.
Red/pink:
5.
6.
Brown/black:
Green/blue:

C. List the protocol used in the evaluation of the physical characteristics of urine
(box 6-1, page 105)
1.
2.
3.
4.
5.
Explain why this protocol should be followed by all laboratorians when examining urine:
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D. Foam
Presence is not reported but used by the technologist as preliminary evidence for the presence of bilirubin and abnormal amounts of protein

1. White foam:

2. Amber/dark yellow foam:
II. Clarity
A. Refers to the transparency of urine

1. Why is it recommended all laboratory personnel use the same terminology when describing urine clarity?
2. Freshly voided ‘clean catch’ normal healthy urine appears clear. Most urines submitted to the laboratory for analysis appear hazy

3. Describe the appearance of urine using the following clarity terms: a. Clear = b. Hazy (slightly cloudy) =

4. c. d.
List two specimen collection and handling errors that can cause urine to appear hazy or cloudy: a. b.
Cloudy =
Turbid =
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B. Substances contributing to the clarity of urine can be pathologic or nonpathologic
1. Non-pathologic substance: a. Precipitation of crystals:
1) Amorphous urates: pink precipitate in acidic urine
2) Amorphous phosphates: white precipitate in alkaline urine
 b. Spermatozoa and prostate fluid are considered contaminants of normal urine because:
4.
 c. Radiographic contrast media (dye) is present in urine following xray procedures and are considered iatrogenic. What does iatrogenic mean?
 d. Fecal material and many squamous epithelial cells indicate what about the urine specimen?
1)
2) e. Mucus, talc, starch

2. Pathologic substances in urine indicate: a. b. c.

3. List the substances, when present in urine, indicate a pathologic condition a. f. b. c. d. e. g. h. i.
Calculi (stones)
Pus
The degree of clarity should correlate to the microscopic examination
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IV. Odor: Not reported, but noted
A.
Normal urine: ‘aromatic’ odor
 B. Abnormal urine: list the causes for the following abnormal odors
1. Foul/ammonia:
2. Pungent/fetid:
3.
4.
Sweet/fruity:
Mousy/barny:
5.
6.
Maple syrup:
Bleach:
7. Ingestion of foods: asparagus, garlic, onions
V. Urine Concentration
A. Concentration refers to the amount of solutes present in a volume of water and is most often expressed as:
1. Specific Gravity : rapid screen; part of routine UA (urinalysis)
2. Osmolality : more accurate measurement of urine density
B. Specific Gravity (SG) is a measurement of density
1. Definition: the density of a substance compared to the density of an equal volume of pure water at the same temperature
2.
SG = Density of urine_____
Density of equal volume of pure water
Affected by the number and molecular size of solutes in solution
3. Significance of SG: reflects concentrating ability of kidney by measuring dissolved solids in urine a. High specific gravity
1) Indicates a more dense or concentrated urine b.
2) Also may indicate low urinary volume (output)
Low specific gravity
1) Indicates a less dense or dilute urine
2) Also may indicate high urinary volume (output)
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
D. Normal urine specific gravity range (textbook, page 130):
1. SG of pure water: ____________ (physiologically impossible)
2. Highest physiologically possible SG: __________
Lowest physiologically possible SG: __________
3. Presence of radiographic contrast media or mannitol will yield SG value of ________________ when using the refractometer method
(physiologically impossible)
4. Why does the SG measurement vary throughout the day:

E. Abnormal specific gravity: (textbook, page 122, 130)
Define the following terms related to specific gravity:
1. Isosthenuria:
Isosthenuria implies / does not imply renal disease
2. Hyposthenuria:
Hyposthenuria implies / does not imply renal disease
3. Hypersthenuria:
Hypersthenuria implies / does not imply renal disease
F. Specific Gravity Methods of Measurement (textbook, page 109-111)
Urinometer: historical method, lacks accuracy 1.
2. Harmonic Oscillation Densitometry: a. Uses sound waves to measure density b. c.
Sound wave oscillation (frequency) is directly related to density
(increased frequency = increased density)
Used on the semi-automated workstation: IRIS
3. c.
Refractometry
 a. Explain the principle of this method:
 b.
What is the ‘refractive index’?
Refractometers routinely measure the angle at which light passes through a solution and mathematically converts this angle to specific gravity (measurement of density)
CLS 426 Urine and Body Fluid Analysis: Student Lab Rotation
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 d. Three factors affect the refractive index of a solution:
1)
2)
3)
 e.
Why doesn’t temperature affect refractometer measurements?
 f. Specific gravity measurements using refractometry measure
all solutes in solution / only ionic substances including glucose and protein (and radiographic contrast media) g. Calibration of the instrument is checked by the laboratorian using distilled water (1.000) and 5% NaCl (1.022 + 0.001) h. The refractometer scale goes only to 1.035. Specimens above this value can be diluted with d-H2O (1:2 dilution by adding 1 part urine to 1 part d-H2O) and the reading retaken; the last two digits of the reading are multiplied by the dilution factor (x2). j.
Example: reading obtained on the 1:2 dilution of urine is 1.021
1.012 x 2 = 1.042 (reported result)
 i. Advantages of using refractometry to determine specific gravity:
1)
2)
Disadvantage: may need to correct specific gravity measurements due to the presence of high concentrations of glucose and/or protein. Most laboratories do NOT perform these corrections on a routine basis, unless requested by clinician
1) 1 gram/dl of protein will increase SG by 0.003
2) 1 gram/dl glucose will increase SG by 0.004
3) Example: Specific gravity by refractometry = 1.035. If the protein concentration in the urine is 2.0 g/dl, then 0.006 (2 x 0.003) will need to be subtracted from 1.035 giving a
‘corrected’ specific gravity result = 1.029
Example: Specific gravity by refractometry = 1.035. If the glucose concentration in the urine is 4.0 g/dl , then 0.016 (4 x 0.004) will need to be subtracted from 1.035 giving a
‘corrected’ specific gravity result = 1.019
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4.
4) A random urine was submitted for specific gravity measurement by refractometry. The urine was from a patient diagnosed with nephrotic syndrome. The physician requested the refractometer value be corrected for the presence of glucose and protein. Use the following data:
Specific gravity by refractometer: 1.031
Urine protein: 5.0 g/dl
Urine glucose: negative
Corrected specific gravity value:
 k. Refer to figure 6-4 on page 112 of the textbook: Using the schematic viewing field, what is the specific gravity reading for a urine specimen?
Reagent strip method: refer to the Chemical Exam of Urine lecture
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