CHEMICAL EXAMINATION OF URINE

Desiccant

Reagent strips should be stored with what?

Opaque and tightly closed

Reagent strips should be stored with what kind of container?

30 degC (room temp)

Reagent strips should be stored at what temp?

Not frozen

Reagents strip should not be what?

Specific gravity

Density of solution compared with density of similar volume of distilled water at a similar temperature

45 sec

Time for specific gravity dipstick test

1.003-1.005

Normal SG (random)

1.00

SG of water

<1.003

SG of non-urine specimens except for diabetes insipidus

Not a urine

When SG is <1.003, it what?

Diabetes insipidus

When SG is <1.003 but is a urine, it is because of what?

Present radiographic dye

When SG >1.040, it is what?

>1.040

When radiographic dye is present, what is its SG?

Urinometry (urinometer/hydrometer)

Urine determination that requires temperature correction

20 degC

Calibration temperature of urinometry

-0.001

For every 3 degC that the spx temperature is below the calibration temp

+0.001

For every 3 degC that the spx temperature is above the calibration temp

-0.004

Required correction for glucose and protein urinometry:

1 g/dL glucose

-0.003

Required correction for glucose and protein urinometry:

1 g/dL protein

10-15 mL

Urine volume required for urinometry

1.015

Calibration for urinometry:

Potassium sulfate solution SG

Refractometry

Indirect method based on refraction index

15-38 degC

Refractometry compensated to temp

No

Does refractometry need for temperature correction?

Glucose and protein

Refractometry requires correction for what?

1.000 +- 0.001

Refractometry calibration for distilled water (H20)

1.022 +- 0.001

Refractometry calibration for 5% NaCl

1.034 +- 0.001

Refractometry calibration for 9% sucrose

1.015 +- 0.001

Refractometry calibration for 3% NaCl

1.035 +- 0.001

Refractometry calibration for 7% NaCl

Change in pka

Principle of reagent strip reaction for SG

pka

Dissociation constant of polyelectrolyte

Yellow (increase H+)

Positive reaction of reagent strip for SG

Poly bromthymol blue

Reagent of reagent strip multistix for SG

Ethyleneglycoldiaminoethylethertetraacetic acid

Reagent of reagent strip chemstrip for SG

High concentration of protein

False positive for SG

Highly alkaline urine (>6.5)

False negative for SG

Harmonic oscillation densitometry

Based on frequency of soundwave entering a solution changes in proportion to the density of solution

6 mL

IRIS diagnostics required urine volume

4 mL (of 6 ml)

Required urine volume for IRIS slideless microscope

2 mL (of 6 mL)

Required urine volume for IRIS mass gravity meter

pH

Important in the identification of crystals and determination of unsatisfactory specimens

Metabolic acidosis

Metabolic alkalosis

Renal tubular acidosis

Significance of pH

4.5-8.0

Random normal pH

5.0-6.0

1st morning normal pH

>9.0

Unpreserved normal pH

Cranberry juice

High protein diet

Emphysema

Starvation

Dehydration

Diabetes mellitus

Diarrhea

Acid urine causes (CHEMPSDDD)

Hyperventilation

Presence of urease-producing bacteria

Renal tubular acidosis

Old specimens

Vegetarian diet

Vomiting

Alkaline urine cause (HPROW)

60 sec

Reagent strip reaction for pH

Double indicator system

Principle of pH

Red to yellow

pH 4.0-6.0 color strip

Yellow to blue

pH 6.0-9.0 colro strip

Increased pH and H+

What happens in a positive reagent strip for pH?

Methyl red

Bromthymol blue

Reagent of pH

Protein

Most indicative of renal disease;

Produces white foam in urine when shaken

White foam

Protein produces what in urine when shaken?

Albumin

Major serum protein found in urine

<150 mg/day

Normal value of albumin (Henry)

<100 mg/day

Normal value of albumin (Strasinger)

Uromodulin

Tamm-horsfall protein

Pre-anal/overflow proteinuria

Caused by conditions that affect the plasma prior to its reaching the kidney

Hemoglobin

Intravascular hemolysis

Intravascular hemolysis

Hemoglobin in urine

Myoglobin

Muscle injury

Muscle injury

Myoglobin in urine

Increased APRs (acute phase reactants)

Severe infection and inflammation

Multiple myeloma

Proliferation of ig-producing plasma cells (Bence-Jones protein)

Serum electrophoresis and immunofixation electrophoresis

BUP tests

40-60 degC

Urine with multiple myeloma precipitates at what temp?

Cloudy

Appearance of urine with multiple myeloma

100 degC

Urine with multiple myeloma dissolves at what temp?

Renal proteinuria

True renal disease

Diabetic nephropathy

Decrease GFR;

May lead to renal failure

Decreased glomerular filtration rate

Diabetic nephrophathy causes what?

Microalbuminuria

Indicator of diabetic nephropathy

Microalbuminuria

Proteinuria undetectable by routine reagent strip

Ug/min

Mg/24 hrs

What unit does albumin excretion rate use?

0-20

Normal AER ug/min

20-200 ug/min

Microalbuminuria by ug/min

30-300 mg/24 hrs

Microalbuminuria by mg/24hrs

>200 ug/min

Clinical albuminuria by ug/min

Micral test

Test for microalbuminuria;

Strip employing antibody-enzyme conjugate that binds albumin

Enzyme immunoassay

Principle of micral test

Gold-labeled antibody

Beta-galactosidase

Chorophenol red galactoside

Reagent of micral test

0-10 mg/dL

Sensitivity of micral test

Red

Positive result of micral test

White

Negative result of micral test

60 sec

Reaction time of micral test

immunochromographics

Principle of immunodip

1.2-8.0 mg/dL

Sensitivity of immunodip

Antibody coated blue latex particles

Reagent of immunodip

Dilute urine

False negative of immunodip

Sensitive albumin tests (related to creatinine conc. to correct patient hydration)

Principle of albumin:creatine ratio

10-150 mg/dL

Sensitivity to albumin of albumin:creatinine ratio

10-300 mg/dL

Sensitivity to creatinine of albumin:creatinine ratio

Orthostatic/cadet/postural proteinuria

Proteinuria when standing due to increased pressure to renal veins

Negative

1st morning of orthostatic proteinuira result

Positive

1st morning of clinical proteinuira result

Positive

2 hrs after standing of orthostatic proteinuira result

Positive

2 hrs after standing of clinical proteinuira result