Urinalysis Exam 1

Specimen types,

Name some reasons a urine specimen may be rejected

Unlabeled container

Mislabeled container

Specimen not properly preserved

Visibly contaminated

What are the main functions of the kidneys? ***

Removal of metabolic waste products

Regulation of water and electrolytes

Maintenance of acid-base equilibrium

Hormone synthesis

What is the main function of the cortex?

It is the exclusive site of plasma filtration where the glomeruli are located

What is the main function of the medulla?

Contains the loop of henle and the collecting ducts of the nephrons

What is the bowman’s capsule?

A thin-walled sac that encloses the glomerulus

What is the proximal convoluted tubule?

An extension of the Bowman’s capsule. Has a straight and convoluted part

80% of all water and salts are reabsorbed

What is the loop of henle?

A thin descending limb and thick ascending limb

Spans across both the medulla and cortex

What is the distal convoluted tubule?

Forms the collecting duct

Reabsorption and secretion of small molecules take place

Reabsorb water to concentrate urine

How many mLs of urine do you need for a manual test?

10-15 mLs

What kind of cast is this?

RBC cast

(Bottom is degenerative RBC cast)

What kind of cast is this?

WBC cast

What kind of cast is this?

Fatty cast

When do fatty casts occur?

What are the requirements needed to identify urine crystals?

Concentration of solute in urine

urine pH

flow of urine through the tubules

What kinds of crystals can form in acidic urine?

Amorphous urates

Uric acid

Bilirubin

Cholesterol

Cystine

Tyrosine

Leucine

How are amorphous urates formed?

Refrigeration

What could many uric acid crystals indicate?

Gout

Chemotherapy for leukemia

Lesch-Nyhan syndrome

What could cause cholesterol crystals to form?

Nephrotic syndrome and disorders that produce lipiduria

What could cause tyrosine crystals to form?

Severe liver disease and inherited diseases that affect amino acid metabolism

What could cause leucine crystals to form?

Maple syrup urine disease of inherited diseases that affect amino acid metabolism

What kind of crystal is this?

Uric acid

What kind of crystal is this?

Cystine crystal

What kind of crystal is this?

Tyrosine crystal

What kind of crystal is this?

Cholesterol crystal

What kind of crystal is this?

Leucine crystal

What kind of crystal is this?

Bilirubin crystal

What kind of crystal is this?

Amorphous urates

What kind of crystals appear in alkaline urine?

Amorphous phosphate

Triple phosphate

Calcium carbonate

Ammonium biurate

Calcium phosphate

What kind of crystal is this?

Basic pH

Amorphous phosphate

What kind of crystal is this?

Triple phosphate

What kind of crystal is this?

Calcium carbonate

What kind of crystal is this?

Ammonium biurate

What kind of crystal is this?

Calcium phosphate

What kind of crystal is this?

Calcium oxalate

What are the 3 basic renal processes?

Plasma filtration

Tubular reabsorption

Tubular secretion

How is the glomerular filtration rate calculated?

24 hr urine and serum creatinine

Depends on body size, age and sex

What is the renal threshold?

Some analytes have a limitation as to how much solute can be reabsorbed

Ex: Diabetic patients excrete glucose when the plasma threshold is greater than renal threshold

What does the descending limb of the loop of henle reabsorb?

Water

What does the ascending limb of the loop of henle reabsorb?

Solutes

What is the role of the distal convoluted tubule?

To achieve electrolyte and acid-base homeostasis by small adjustments via AVP and aldosterone

AVP makes the distal tubule more permeable to water (when dehydrated)

What are the 5 main functions of the kidney? ******

Homeostasis

Acid-base balance

Nitrogenous waste excretion

Hormone function

Protein conservation

What hormone do the kidneys play a major role in producing for red blood cell production?

Erythropoietin

What protein is used to distinguish between disorders that affect the glomeruli and the renal tubules?

Beta 2-microglobulin

What is nocturia?

More than 500 mL of urine at night

What is polyuria?

More than 3 L of urine each day

What is oliguria?

Less than 400 mL of urine per day

What is anuria?

Lack of urine excretion

What is it called when specific gravity is consistently low (<1.010)? ***

Hyposthenuria

What does hyposthenuria indicate? ***

Concentration problem

Collagen disease, pyelonephritis, hypertension, protein malnutrition, diabetes insipidus (renal)

What is it called when the specific gravity is consistently high (>1.010)? ***

Hypersthenuria

What does hypersthenuria indicate?

Hepatic disease, congestive heart failure, dehydration, proteinuria, diabetes mellitus (pancreas)

What could cause a false high specific gravity?

X-ray dyes

What is it called when specific gravity is consistently fixed at 1.010? ***

Isosthenuria

What is the average specific gravity of urine?

1.015-1.025

What could cause acidic urine?

High protein diet

Medications

Acidosis

What could cause alkaline urine?

Diets high in vegetables and dairy products

Medication (like sodium bicarbonate)

Bacteria (Urea splitting like Pseudo)

What is unique about Bence Jones proteins?

Indicator of multiple myeloma

Precipitates at temps between 40-60*C and redissolves around 100*C

What is sulfosalicylic acid used for?

Confirming protein concentration

Why does a negative nitrite test not automatically mean an absence of bacteria?

Some bacteria do not reduce nitrate to nitrite

What ketone can not be detected on strip tests?

Betahydroxybutric acid

What test is used to confirm positive bilirubin dipstick tests?

Ictotest

What does the Ehrlich’s reaction test for?

Urobilinogen

What is the amount of urobilinogen expected in a healthy individual?

Normal

What is the amount of urobilinogen expected in a patient with hemolytic disease?

Increased

What is the amount of urobilinogen expected in a patient with hepatic disease?

Increased

What is the amount of urobilinogen expected in a patient with biliary blockage?

Absent or decreased

What is the amount of bilirubin expected in a healthy patient?

Negative

What is the amount of bilirubin expected in a patient with hemolytic disease?

Negative

What is the amount of bilirubin expected in a patient with hepatic disease?

Increased or decreased

What is the amount of bilirubin expected in a patient with biliary blockage?

Increased

What are hyaline casts composed of?

Uromodulin protein matrix

What could cause an increase in hyaline casts in the urine?

Strenuous exercise

Dehydration

Fever

Emotional stress

Renal disease

Congestive heart failure

When might a patient have waxy casts in their urine?

During severe chronic renal failure

When might a patient have fatty casts in their urine?

Nephrotic syndrome

Toxic tubular necrosis

Diabetes mellitus

When may you find monohydrate forms of calcium oxalate crystals in urine?

In poison centers where children have ingested antifreeze (ethylene glycol)