Urinalysis and Body Fluids Practice Flashcards

A comprehensive set of 100 vocabulary-style flashcards covering urinalysis, body fluid analysis (CSF, synovial, amniotic), and renal physiology based on the lecture notes.

Random urine specimen

A urine specimen collected at any time for urinalysis.

First morning urine specimen

A concentrated specimen collected upon waking; it is the best type for detecting early pregnancy.

Midstream clean-catch urine specimen

A specimen preferred for culture because it is non-invasive and flushes out normal flora from the urethra, reducing contamination.

Catheterization

A method of urine collection involving the insertion of a tube into the bladder.

Suprapubic aspiration

A method of urine collection involving a needle inserted through the abdominal wall into the bladder.

Permissible room temperature storage time

Urine specimens can be stored at room temperature for a maximum of $2$ hours before analysis.

Effect of prolonged standing on Nitrite

Nitrite levels increase due to bacterial growth.

Effect of prolonged standing on pH

pH increases because urea is converted to ammonia.

Effect of prolonged standing on Turbidity

Turbidity increases due to bacterial growth and crystal precipitation.

Effect of prolonged standing on Glucose

Glucose levels decrease due to glycolysis by bacteria and yeast.

Effect of prolonged standing on Ketones

Ketones decrease due to volatilization or evaporation.

Effect of prolonged standing on Bilirubin

Bilirubin levels decrease due to exposure to light.

Effect of prolonged standing on Urobilinogen

Urobilinogen levels decrease due to oxidation.

Effect of prolonged standing on Cells and Casts

Cells and casts decrease due to lysis or disintegration.

Urine specimen labeling procedure

Always label the container wall, never the lid, including patient name, ID, date, and time of collection.

Boric Acid

A preservative that maintains pH and inhibits bacterial growth; commonly used for protein and culture transport.

Acetic Acid

A 24-hour urine collection preservative often used for calcium or hormone testing.

Formalin

A preservative used to preserve cellular elements and sediment in urine.

Sodium Fluoride

A preservative used to prevent glycolysis for glucose testing.

Refrigeration (non-chemical preservation)

The most common non-chemical method used during collection; it may result in the precipitation of amorphous crystals.

24-hour urine collection completeness

Ensured by using time-marked containers for accurate quantitative testing.

False-negative microscopic findings

Occur if urine is not mixed before analysis, as heavy elements like RBCs, WBCs, and casts settle at the bottom.

Physical examination parameters

The core parameters include odor, clarity, color, and pH.

Red urine substance

Indicates the presence of Hemoglobin, Red Blood Cells, Myoglobin, Porphyrin, or Uroerythrin.

Yellow-Brown / Yellow-Green urine

Indicates the presence of Bilirubin or Biliverdin.

Yellow-Orange urine

Indicates the presence of Bilirubin, Urobilin, or the drug Pyridium.

Bright Yellow urine

A color often associated with the intake of Vitamin C.

Brown-Black urine

Indicates Methemoglobin, Homogentisic Acid (Alkaptonuria), or Melanin.

Blue urine

Indicates Indican, which is associated with Tryptophane Metabolic Disorder.

Port Wine urine

A distinct color indicating the presence of Porphyrin.

Cloudy urine clinical significance

Indicates WBCs, RBCs, bacteria, yeast (suggesting infection), or non-pathological amorphous material.

Specific gravity

The ratio of the weight of a volume of urine to the weight of the same volume of distilled water.

High specific gravity threshold

A value greater than $1.030$, commonly caused by dehydration, Diabetes mellitus, or proteinuria.

Refractometer

The instrument commonly used to measure the specific gravity of urine.

Effect of dehydration on urine color

Urine becomes Dark Yellow or Amber due to a higher concentration of urochrome.

Specific gravity in dehydration

Typically rises above $1.025$ or $1.030$ because there are more dissolved solids relative to water.

Refrigeration effect on clarity

Causes amorphous urates or amorphous phosphates to precipitate, making the urine look cloudy.

Effect of room temperature on urine odor

A strong ammonia smell develops as bacteria convert urea into ammonia.

pH dipstick principle

Uses $2$ indicators that provide a wide spectrum of color changes.

Protein dipstick principle

Protein error of indicators; the dye changes color at a fixed strip pH of $3.5$ in the presence of protein.

Glucose dipstick principle

Glucose oxidase method, also known as the double sequential enzyme method.

Ketones dipstick principle

Sodium nitroprusside reacts with ketones to produce a purple color.

Blood dipstick principle

A 2-step enzymatic procedure using peroxidase.

Bilirubin dipstick principle

Diazonium salt reacts with Bilirubin to produce a bluish/purple color.

Urobilinogen dipstick principle

Ehrlich's reaction, using Para-dimethylaminobenzaldehyde to form a peach to pink color.

Nitrite dipstick principle

Diazo reaction that forms a diazonium compound.

Leukocytes dipstick principle

Leukocyte esterase splits an ester to form a pyrrole compound.

Specific Gravity dipstick principle

Based on the pKa change of a polyelectrolyte.

Positive leukocyte esterase test

Indicates the presence of leukocytes, a condition known as pyuria.

Albumin

The specific protein to which the reagent strip is most sensitive.

Proteinuria causes

Renal disease, Multiple Myeloma (Bence-Jones proteins), Orthostatic Proteinuria, and strenuous exercise.

Clinitest

A copper reduction test used to identify reducing sugars in urine.

Acetest

The confirmation test for the presence of ketones.

Ictotest

The confirmatory test for bilirubin in urine.

Positive nitrite test significance

Signifies a Urinary Tract Infection (UTI) caused by nitrate-reducing bacteria.

Conditions causing alkaline urine

Vegetarian diet, infection, or an old specimen.

Conditions causing acidic urine

Metabolic or respiratory acidosis, high protein diet, or cranberry juice.

Normal urine pH range

Between $4.5$ and $8.0$.

False-positive protein result

Often caused by highly alkaline urine.

Ascorbic acid interference

Causes false negatives in glucose, blood, bilirubin, and nitrites.

Hematuria

The presence of intact red blood cells (RBCs) in urine, causing a cloudy or smoky red appearance.

Hemoglobinuria

The presence of free hemoglobin in urine after RBC destruction, appearing as clear red urine.

Myoglobinuria

The presence of myoglobin from muscle breakdown, appearing as clear dark brown or tea-colored urine.

Urobilinogen clinical significance

Increased levels suggest liver damage or hemolytic disease.

Urine sediment preparation

Centrifuge $10-15 mL$ of urine for $5$ minutes, pour off supernatant, and resuspend sediment for microscopy.

Red blood cells (microscopy)

Small round pale yellow to red discs without a nucleus; may appear as 'ghost cells' in dilute urine.

White blood cells (microscopy)

Usually indicate inflammation or infection; often seen in urinary tract infections.

Renal tubular epithelial (RTE) cells

The most significant epithelial cells; their presence indicates kidney tubular damage or graft rejection.

Hyaline casts

Clear, colorless casts with smooth borders made of Tamm-Horsfall protein; seen in normal urine after exercise.

Granular casts

Opaque casts containing granules from degenerated cells; they indicate kidney disease or tubular damage.

Waxy casts

Indicate advanced, severe renal disease or chronic kidney failure; they represent degenerated cellular casts from urine stasis.

Oval fat bodies

Highly refractile fat droplets in renal tubular epithelial cells, associated with Nephrotic syndrome.

Uric acid crystals

Yellow-brown rosettes or wedges found in acidic urine; associated with gout or high purine metabolism.

Calcium oxalate dihydrate

Envelope-shaped crystals with an 'X' in the middle, found in acid or neutral urine.

Amorphous urates

Pink to 'brick dust' sediment in acidic urine with no clinical significance.

Triple Phosphate crystals

Colorless 'coffin lid' shaped crystals found in alkaline or neutral urine.

Ammonium biurate crystals

Yellow-brown 'thorny apples' found in old alkaline specimens, often associated with urea-splitting bacteria.

Cystine crystals

Colorless hexagonal plates in acidic urine, indicating inherited cystinuria.

Leucine crystals

Yellow crystals with concentric circles in acidic urine, indicating liver disease.

Tyrosine crystals

Colorless to yellow needles in acidic urine, indicating liver disease.

Cholesterol crystals

Colorless notched plates found in acidic urine, associated with Nephrotic syndrome.

Radiographic dye crystals

Colorless flat plates found after IV contrast imaging; associated with very high specific gravity.

RBC casts significance

Associated with Glomerulonephritis and strenuous exercise.

WBC casts significance

Associated with Pyelonephritis and Acute Interstitial Nephritis (AIN).

Yeast

Common in diabetes mellitus or vaginal candidiasis; identified by budding or pseudohyphae.

Trichomonas

A parasite identified by rapid, jerky motility in fresh urine samples.

Starch artifact

Contamination from medical gloves; shows a 'Maltese cross' under polarized light.

Antidiuretic hormone (ADH)

Produced in the hypothalamus and released by the posterior pituitary to regulate water balance.

CSF Tube 1

Used for Chemistry / Serology (Protein, Glucose, Lactate) as it is least affected by puncture-introduced contaminants.

CSF Tube 2

Used for Microbiology (Gram stain, Culture) as it is less likely to be skin flora contaminated.

CSF Tube 3

Used for Hematology (Cell count and Differential) because it contains the fewest traumatically introduced cells.

Xanthochromia

Pink, yellow, or orange CSF supernatant indicating intracranial hemorrhage that occurred at least $2$ hours prior.

Normal adult CSF Glucose

Approximately $60-70 \%$ of blood glucose.

Normal adult CSF Protein

Approximately $15-45\,mg/dL$.

Bacterial meningitis CSF profile

Significantly increased protein, decreased glucose, and predominant neutrophils.

Viral meningitis CSF profile

Mildly increased protein, normal glucose, and predominant lymphocytes.

India Ink stain

Used specifically to visualize the capsule of Cryptococcus neoformans in CSF.

Anuria

Virtually no urine output, defined as less than $100\,mL/day$.

Oliguria

Low urine output, defined as less than $400\,mL/day$.

Alpha-fetoprotein (AFP)

Tested in amniotic fluid to screen for Neural Tube Defects (NTD) like spina bifida.