Body Fluids Master Set

Weeks 1-5

What does the color of urine depend on?

What does the color of urine depend on?

• physical activity

• dietary pigments

• drugs

• metabolites

• pathologic conditions

The main color of urine is caused by:

urochrome (product of endogenous metabolism)

Urochrome is increased in what?

thyroid conditions, fasting states, and urine standing at room temp

uroerythrin

pink, seen in refrigerated samples, precipitation of urates

urobilin

breakdown of bilirubin, orange/brown when urine is not fresh

Clinical significance of dark yellow/amber/orange urine

presence of bilirubin

clinical significance of nonpathogenic yellow/orange urine

phenazopyridine/pyridium/Azo dyes (UTI treatment)

Red/pink/brown urine

• blood in the sample

• acidic pH turns it brown

• fresh brown: glomerular bleeding

What would you expect to see in a UA containing porphyrins?

• port wine color

• red color from the oxidation of porphobilinogen

What could a nonpathogenic red urine be caused by?

• menstrual contamination

• pigmented foods (beets)

• medications (rifampin and Phens)

Brown or black urine can be caused by what?

• melanin (malignant melanoma)

• homogentisic acid (alkaptonuria)

• meds (-opa, phenol derivatives, flagyl)

Blue or green urine is indicative of what?

bacterial infections (pseudomonas)

Purple staining may occur in catheter bags because?

indicant in urine or bacterial infection (kleb or providencia)

The presence of white foam could mean?

presence of albumin or possible renal disease

Yellow foam means

the presence of bilirubin or possible liver disease

What is clarity?

the transparency or turbidity of urine sample

Cloudiness of urine can be caused by what?

crystal precipitation (morphous phosphates and carbonates)

What are the classifications of clarity?

clear, hazy, cloudy, turbid, milky

what are some non-pathologic causes of turbidity?

vaginal cream, talcum powder, mucus, sq. epithelial cells, crystals, fridge, semen or poop, radiographic contrast media

Pathologic causes of turbidity:

RBC, WBC, UTI, trichomonads, lymph fluid, abnormal crystals, lipids, non sq epithelial

Specific gravity

density of a solution compared with the density of similar volume of distilled water at similar temps.

What does SG measure?

the kidneys ability to concentrate/dilute urine

Isosthenuric

urine SG that stays at 1.010

Hyposthenuric

urine SG that are below 1.010

Hyperthenuric

SG above 1.010

What is the healthy reference range for urine SG?

1.003 to 1.035 (less than is not urine and more than has interfering substances)

SG is what to the volume?

inversely proportional

Urinometry (direct)

determines SG following the administration of X-ray dye

Refractometry (indirect)

uses small volume and compensates for temperature (corrections needed from glucose and protein)

Chemical reagent strip (indirect)

rxn based on the change in pKa of polyelectrolyte in an alkaline medium

What does a refractometer measure?

the ratio of velocity of light in air to the velocity of light in a solution (velocity depends on # of dissolved particles)

The odor of urine depends on what?

• diet/medication

• improper storage

• pathological conditions

A fruity/sweet odor is indicative of what?

ketone bodies produced

lack of odor

tubular necrosis

putrid/foul smell

UTI

Maple syrup smell

MSUD

Mousy odor

PKU

rancid odor

tyrosinemia

sweaty feet smell

isovaleric acidemia

cabbage smell

methionine malabsorption

bleach smell

contamination

What does the reagent strip consist of?

chemical-impregnated absorbent pads attached to a plastic strip

What do rapid means test for (reagent strip)?

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

possible error/interferences

• unmixed

• extended immersion

• run-over from other reagents

• temp, humidity

• interfering substances (AZO)

• technical carelessness

• color blind

Healthy pH ranges of urine

• morning: acidic

• following meals: alkaline tide

• random samples: 4.5-8.0

What is the significance of urine pH?

• diagnosis of resp./metabolic acid or alkalosis

• renal calculi formation

• treatment of UTIs

• ID of crystals

• defects in tubular secretion and reabsorption

pH pad reaction?

double-indicator system (methyl red and bromothymol blue)

Protein in the urine is most indicative of what?

renal disease

What protein is the reagent strip specific to?

albumin

Prerenal proteinuria

• affects plasma before reaching kidneys

• not discovered in routine urinalysis

• Bence Jones proteins

Renal proteinuria

• TRUE renal disease

• glomerular membrane is damaged, selective filtration is impaired

What conditions, associated with renal proteinuria, are irreversible?

• amyloid material

• toxic exposure

• lupus

• strep glomerulonephritis

What reversible conditions are associated with renal proteinuria?

• strenuous exercise

• dehydration

• hypertension

• pre-eclampsia

Microalbuminuria

• common for diabetes mellitus

• diabetic nephropathy leads to dec glomerular filtration

  • prevented by control of blood glucose and hypertension

Orthostatic (postural) proteinuria

protein excreted when in vertical position

Tubular proteinuria

• albumin can’t be absorbed anymore

• toxic substance/heavy metal exposure

• severe viral infections

• Fanconi’s syndrome

Postrenal proteinuria

• protein added to specimen after it passes through lower UT

• bacterial/fungal infections, inflammatory conditions, menstrual contamination, trauma

Interferences that can cause false + on reagent strip for albumin:

highly buffered alkaline urine and pigmented specimens (AZO)

Interferences that cause false = on reagent strip for albumin:

proteins other than albumin or microalbuminuria

What system does the protein pad use?

protein error of indicators system

Glucose is filtered by …. and reabsorbed by ….

filtered: glomerulus

reabsorbed: PCT

A positive glucose result is indicative of what?

renal threshold reached

hyperglycemia (pancreatitis, thyroid issues, Cushing syndrome, hormones, and DIABETES)

Interferences for glucose reaction:

false +: contamination w/ peroxide or bleach (strong oxidizers)

false =: presence of reducing substances (ascorbic acid and salicylates)

glucose pad reaction:

glucose oxidase rxn (2 steps)

In what conditions would you find ketones in the urine?

• fat is used as energy source

• diabetes mellitus

• bulimia

• anorexia

• keto diet

What does the ketone pad measure?

acetoacetic acid

What is the primary reagent in the ketone rxn?

sodium nitroprusside

interferences for the ketone reaction:

false +: pigmented urine, meds w/ sulfhydryl groups

false =: old/improperly preserved specimens

Presence of intact blood in the urine

hematuria (red and cloudy)

Presence of destructed blood in the urine

hemoglobinuria (red and clear)

Hematuria is related to?

disorders of renal or genitourinary origin

Hemoglobinuria is related to ?

disorders where the amount of free Hgb present exceeds the haptoglobin content

Myoglobinuria is related to?

disorders of muscle destruction

Interferences for the blood pad:

false +: oxidizing agents, povione-iodine, bacterial infections

false =: ascorbic acid, formalin, high protein/nitrites

What is the principle reaction of the blood pad?

pseudoperoxidase activity of Hgb

What is bilirubin?

degradation product of hemoglobin

Bilirubin in the urine can provide early indication of?

liver disease

Causes of bilirubinemia

hepatitis, cirrhosis, bile duct obstruction (gallstones), and pancreatic cancer

What are RBCs broken down into?

iron, protein, protoporhyrin (turned into bilirubin)

Interferences for bilirubin pad:

false +: pigmented urine, indican

false =: light exposure, ascorbic acid, high nitrites

Urobilinogen

• produced from bilirubin by intestinal bacteria

• liver disease or hemolytic disorders

What can cause a false negative urobilinogen result?

• old specimen

• light exposure (urobilinogen to urobilin)

• inc nitrite

• preservation in formalin

What can cause a false positive urobilinogen result?

• porphobilinogen

• highly pigmented urine

• drugs

• testing after eating

What is the reaction called on the bilirubin pad?

diazo reaction

What is the main reagent on the urobilinogen pad?

Ehrlich reagent

bile duct obstruction bili/urobili results

+ bili normal urobili

liver damage bili/urobili results

pos or neg bili pos urobili

Hemolytic disease bili/urobili results

neg bili pos urobili

What does the nitrite test show?

presence of bacteria in the urine (UTI and the itises)

What is the name of the nitrite rxn on the pad?

Greiss reaction

Nitrite pad interferences

false +: pigmented or old urine

false =: high SG, ascorbic acid, urobili

Leukocyturia

WBCs in urine

What is the Leukocyte esterase test looking for?

presence of esterase in granulocytic WBCs and monos (doesn’t measure conc.)

what type of reaction is used on the LEU pad?

hydrolysis

interferences on the LEU pad:

false +: oxidizing agent, formalin, eos, trichomonas

false =: high protein, glucose, and SG, ascorbic acid, antibiotics

rection for SG pad

change of pka in an alkaline medium

interferences of SG pad:

false +: high protein

false =: high protein or high alkaline

What is the confirmatory test for reducing agents?

Copper reduction test (Clinitest)

Confirmatory test for bilirubin

Ictotest tablet

Confirmatory test for Ketones

acetest