MT 35 (LAB): Urinalysis Parameters and Reagents

Parameters for the Chemical Examination of Urine

pH, protein, glucose, ketones, blood, bilirubin, urobilinogen, nitrite, leukocytes and specific gravity

Identify the principle behind the pH test in urinalysis.

Double-indicator system (methyl red and bromthymol blue)

What is the reading time for the pH pad?

60 seconds

True or False: The pH test detects free hydrogen ions concentration.

True

Fill in the blank: The pH scale on strips ranges from ________ to ________.

5.0–8.0

Identify the Multistix indicators used for pH measurement.

Methyl red and bromthymol blue

True or False: Protein in urine can affect pH readings.

True

Identify the principle of the protein test.

Protein-error of indicators

What is the reading time for the protein pad?

60 seconds

Fill in the blank: The protein pad changes from ________ to ________ if albumin is present.

Yellow to green-blue

What protein is primarily detected by reagent strips?

Albumin

True or False: Chemstrip is more sensitive to low concentrations of albumin.

True

What is the minimum sensitivity of the protein pad on Multistix?

15–30 mg/dL

Fill in the blank: Protein results are reported as ________.

Negative, trace, 1

, 2

, 3

, 4

Identify the principle behind the glucose test.

Double sequential enzyme reaction (oxidase-peroxidase)

What are the two enzymes used in glucose testing?

Glucose oxidase and peroxidase

True or False: The glucose pad produces a colored compound through oxidation.

True

What is the reading time for the glucose pad?

30 seconds

Fill in the blank: Glucose readings are reported in ________ or as levels.

mg/dL

Identify the glucose pad sensitivity.

75–125 mg/dL

What causes false negatives in glucose tests?

Old specimens (bacterial consumption)

Identify the principle of the ketone pad.

Sodium nitroprusside reaction (Legal's test)

True or False: Ketone strips detect acetoacetate only.

True

What is the reading time for the ketone pad?

40 seconds

Fill in the blank: Ketones are reported as ________.

Negative, small, moderate, large

Identify one interfering substance in ketone testing.

Levodopa

What is the principle behind the blood test pad?

Pseudoperoxidase activity of hemoglobin/myoglobin

True or False: The blood pad reacts with both hemoglobin and intact RBCs.

True

What is the reading time for the blood pad?

60 seconds

Fill in the blank: Blood results are reported as ________.

Negative, trace, small, moderate, large

What colors indicate blood on the pad?

Speckled green (RBCs), uniform green (Hgb/Myoglobin)

Identify the principle behind the bilirubin test.

Diazo reaction (formation of azo dye)

What is the reading time for the bilirubin pad?

30 seconds

True or False: Only conjugated bilirubin is detected on strips.

True

What causes interference in bilirubin testing?

Phenazopyridine, ascorbic acid

Fill in the blank: Bilirubin is reported as ________.

Negative, small, moderate, large

What is the principle of the urobilinogen test?

Ehrlich’s aldehyde reaction

What is the reading time for urobilinogen?

60 seconds

True or False: Urobilinogen is always present in small amounts in normal urine.

True

What is the reporting range for urobilinogen?

0.2–8.0 EU/dL

Identify the principle of the nitrite test.

Greiss reaction

What is the reading time for the nitrite pad?

60 seconds

Fill in the blank: A ________ color indicates a positive nitrite test.

Pink

True or False: Nitrite test requires bacteria to reduce nitrate.

True

What is the sensitivity of the nitrite pad?

105 CFU/mL for nitrate-reducing bacteria

What is the principle of leukocyte esterase test?

Detection of esterase activity in granulocytes

What is the reading time for leukocyte pad?

2 minutes

Fill in the blank: Leukocyte results are reported as ________.

Negative, trace, small, moderate, large

True or False: Lymphocytes yield a negative leukocyte esterase result.

True

What is the principle of the specific gravity test on Chemstrip?

Polyelectrolyte indicator-based reaction

What is the reading time for SG pad?

45 seconds

True or False: Bromothymol blue changes color based on ionic concentration.

True

How is specific gravity reported?

As a numerical value (e.g., 1.005–1.030)

Identify one factor that can affect SG accuracy.

High glucose or protein levels

What is the principle of the ascorbic acid pad (when present)?

Reduction of indicators to prevent interference

True or False: Ascorbic acid can cause false negatives in blood and bilirubin tests.

True

Fill in the blank: A positive ascorbic acid test indicates ________.

Potential interference in other parameters

Fill in the blank: The principle of the nitrite test is based on the ________ reaction.

Greiss

True or False: The nitrite pad detects bacteria that reduce nitrate to nitrite.

True

What is the primary source of nitrate in the body for the nitrite test?

Dietary vegetables

Fill in the blank: The leukocyte esterase pad detects ________ enzyme activity.

Granulocyte

True or False: Lymphocytes do not give a positive leukocyte esterase result.

True

What is the time for reading the leukocyte esterase pad?

2 minutes

Fill in the blank: The SG (specific gravity) pad uses a ________ system to detect ionic concentration.

Polyelectrolyte

What indicator dye is used in the SG test pad of Chemstrip?

Bromothymol blue

True or False: The SG pad color shifts based on urine ionic strength.

True

What is the reading time for the specific gravity pad?

45 seconds

Fill in the blank: Ascorbic acid can cause false negatives for ________ and ________.

Blood, bilirubin

True or False: The ascorbic acid pad is a preventive screen for false negatives.

True

What type of pad color change indicates ascorbic acid presence?

Colorless to orange

Fill in the blank: The normal range for urine specific gravity is ________.

1.005–1.030

What reaction is used in the bilirubin test?

Diazo reaction

True or False: Microalbumin detection is more specific for early kidney damage.

True

What condition warrants testing for microalbuminuria?

Diabetes mellitus

Fill in the blank: Microalbumin is reported in ________ units.

mg/dL

True or False: Creatinine is measured to normalize urine albumin concentration.

True

What is the significance of the albumin-to-creatinine ratio?

Estimates 24-hour albumin excretion

Fill in the blank: Glucose oxidase produces ________, which reacts with peroxidase.

Hydrogen peroxide

True or False: Multistix detects protein via tetrabromophenol blue dye.

True

What is the reaction type for protein detection in urinalysis?

Protein-error of indicators

Fill in the blank: The urobilinogen pad uses ________ as its chemical principle.

Ehrlich’s aldehyde reaction

True or False: The bilirubin pad only detects conjugated bilirubin.

True

Identify the reaction responsible for ketone testing.

Sodium nitroprusside reaction

Fill in the blank: Myoglobin and hemoglobin show a uniform ________ color on the blood pad.

Green

True or False: The SG pad is affected more by ionic solutes than glucose or protein.

True

What is the typical report format for leukocyte esterase?

Negative, trace, small, moderate, large

Fill in the blank: Urine pH may influence the accuracy of the ________ test pad.

Protei