Urinalysis & Body Fluids

first morning specimen (description and uses (4))

patient void upon waking, most concentrated and specimen of choice

1. substances requiring concentration or refrigeration

2. confirm postural proteinuria

3. cytology samples

4. routine urinalysis

random urine specimen (description and uses (3))

collected anytime, most convenient, least accurate

1. routine urinalysis

2. cytology studies (requires hydration)

3. fluid depravation tests

timed collection (description and uses (4))

all urine collected during time interval

1. albumin, microalbumin, creatinine

2. clearance tests

3. quantitative chemical analysis

4. evaluation of fistula

random void (technique and purpose (1))

no patient prep, just void into container

1. routine urinalysis

midstream "clean catch" (technique and purposes (2))

void into toilet, void into cup, void rest into toilet

1. routine urinalysis

2. urine culture

catheterized (technique and purposes (3))

sterile catheter inserted through urethra to bladder and urine accumulates into bag, or past bladder into ureters

1. bacterial culture

2. routine screening

3. determine and differentiate between kidney infections

suprapubic aspiration (technique and purposes (2))

directly aspirated from bladder using sterile syringe

1. bacterial cultures

2. infants

pediatric collection (technique and purposes (3))

urine collection bag, high risk for contamination

1. children

2. routine screening

3. quantitative assays

most common way to preserve urine

refrigeration

things increasing in unpreserved urine (2)

1. bacteria

2. nitrite

exclusive site of plasma filtration

cortex

areas of kidney (2)

cortex (outer) and medulla (inner)

flow of urine through kidney

kidneys -> glomerulus -> PCT -> descending limb -> loop of henle -> ascending limb -> DCT -> collecting duct -> papilla -> minor calyx -> major calyx -> renal pelvis -> ureter -> bladder -> urethra

components of glomerular filtration system (3)

1. capillary endothelial cells

2. basement membrane

3. podocytes

how glomerular filtration works

ultrafiltration is passive, nonselective process based on size and charge

primary functions of kidney (5)

1. filtration of blood

2. acid-base

3. fluid/electrolyte balance

4. urine formation

5. hormone regulation

direct active transport

movement of substances across membrane against gradient - exchange of substances

indirect active transport

movement of substances across membrane against gradient - one solute pairs with another

passive transport

requires no energy, movement across membrane along gradient

tubular reabsorption

takes back substances necessary for maintenance of body homeostasis and function

tubular secretion

eliminates waste and other substances not normally present in plasma, adjusts acid-base equilibrium

water is always what kind of transport

passive

PCT function (3)

1. reabsorb 66% of water potassium, chloride, urea - passive

2. reabsorb 100% of glucose, amino acids, proteins - indirect active

3. reabsorb sodium, chloride, and other solutes - active

descending loop of henle function (1)

1. water and urea - passive

ascending loop of henle function (1)

1. sodium, chloride, urea - passive

NO WATER

DCT function (2)

1. sodium, chloride, sulfate, uric acid - active

2. water - passive

collection duct function (3)

1. water and chloride - passive

2. sodium - active

3. water and urea - passive

first mechanism

hydrogen and bicarbonate

second mechanism

phosphate

third mechanism

ammonia

aldosterone/RAAS (reabsorbs, conditions released, parts of nephrons acted on, where secreted from)

1. sodium

2. decreased sodium, decreased blood pressure, decreased blood volume

3. DCT and collecting duct

4. kidney

ADH (reabsorbs, conditions released, parts of nephrons acted on, where secreted from)

1. water

2. decreased arteriole pressure

3. DCT and collecting duct

4. hypothalamus

RAAS system

renin released -> angiotensin II -> aldosterone

polyuria

excessive urine (>3L)

oliguria

decreased urine (<400mL)

anuria

no urine

nocturia

excessive urination at night

osmolality

expression of solute concentration in osmoles of solute particles per kg solvent

specific gravity

expression of solute concentration that relates density of urine to water

processes of urine formation (3)

1. glomerular filtration

2. tubular reabsorption

3. tubular secretion

normal urine volume

1200 mL/day

normal urine solutes (8)

1. urea

2. chloride

3. sodium

4. potassium

5. phosphate

6. sulfate

7. creatinine

8. uric acid

substance that best differentiates urine

creatinine

creatinine clearance test

most commonly used clearance test for assessment of glomerular filtration rate (GFR)

creatinine clearance test equation

((U x V)/P)(1.73 m2/SA)

specific gravity - test reaction

specific gravity - test principle

protons released from polyelectrolyte decreases pH

leukocyte esterase - test reaction

leukocyte esterase - test principle

esterase reaction followed by azo coupling reaction

leukocyte esterase - clinical significance

small amount normal, detects WBC

leukocyte esterase - false positives (2)

1. contamination

2. drugs or food causing sample to be red or pink

leukocyte esterase - false negatives (3)

1. increased protein or glucose

2. high specific gravity

3. antibiotics and strong oxidizers

leukocyte esterase - specificity

doesn't detect lymphocytes

leukocyte esterase - sensitivity

1. chemstrip - 10 WBC/microliter

2. multistix - 11-36 WBC/microliter

CHEMSTRIP MORE SENSITIVE

nitrite - test reaction

nitrite - test principle

diazo reaction followed by azo coupling reaction

nitrite - clinical significance

UTIs

nitrite - false positives (2)

1. colored substances masking results

2. improper storage

nitrite - false negatives (2)

1. ascorbic acid

2. factors that inhibit nitrite formation

nitrite - specificity

needs enough time to convert, bacteria has to have enzyme to convert, nitrate must be present

nitrite - sensitivity

1. chemstrip - 0.05 mg/dL

2. multistix - 0.06 mg/dL

CHEMSTRIP MORE SENSITIVE

glucose - test reaction

glucose - test principle

double sequential enzyme reaction

glucose - clinical significance

hypergycemia, defective tubular absorption, diabetes mellitus

glucose - false positives (2)

1. strong oxidizing agents

2. peroxidase contaminants

glucose - false negatives (2)

1. ascorbic acid

2. improper storage

glucose - specificity

only detects glucose, not other reducing sugars

glucose - sensitivity

1. chemstrip - 40 mg/dL

2. multistix - 75-125 mg/dL

CHEMSTRIP MORE SENSITIVE

bilirubin - test reaction

bilirubin - test principle

azo coupling reaction

bilirubin - clinical significance

any detectable amount clinically significant, elevated levels in different disease states, post-hepatic conditions

bilirubin - false positives (1)

1. drug induced color changes

bilirubin - false negatives (3)

1. ascorbic acid

2. high nitrite

3. improper storage

bilirubin - sensitivity

1. chemstrip - 0.5 mg/dL

2. multistix - 0.4-0.8 mg/dL

ABOUT EQUALLY SENSITIVE

urobilinogen - test reaction

urobilinogen - test principle

classic ehrlich's reaction

urobilinogen - clinical significance

small amount normal, prehepatic conditions

urobilinogen - false positives (2)

1. any other ehrlich's substance

2. atypical colors

urobilinogen - false negatives (2)

1. formalin

2. improper storage

urobilinogen - sensitivity

1. chemstrip - 0.4 mg/dL

2. multistix - 0.2 mg/dL

bilirubin metabolism

RBC -> breaks into heme molecule -> unconjugated bilirubin + albumin sent to liver -> liver converts to conjugated bilirubin + glucuronic acid -> small intestine reduces bilirubin into urobilinogen -> urobilinogen reabsorbed or excreted into urine

prehepatic conditions

increased urobilinogen in urine and no bilirubin, hemolytic conditions

hepatic conditions

both urobilinogen and bilirubin in urine, liver diseases

posthepatic conditions

increased bilirubin in urine, obstructions

neutrophil functions (2)

1. protect body from infection using phagocytosis

2. common in bacterial infections

lymphocyte functions (3)

1. antibody production

2. mediate immune response

3. killing tumor cells or virus infected cells

monocyte functions (3)

1. phagocytosis

2. antigen presentation

3. removal of debris and dead cells

eosinophil functions (3)

1. allergic reaction

2. chronic inflammation

3. parasites

basophil functions (3)

1. mediate immune response

2. initiate allergic inflammation

3. hypersensitivity reactions

fluids mesothelial cells can be found in

pleural, peritoneal, pericardial

factors controlling serous fluid formation (4)

1. permeability of capillaries in parietal membrane

2. hydrostatic pressure in these capillaries

3. oncotic pressure produced by presence of plasma proteins

4. absorption of fluid by lymphatic system

synovial fluid functions (2)

1. joint lubrication

2. nutrients for articular cartilage

synovial fluid formation

ultrafiltrate of plasma across synovial membrane + synoviocyte secretions

arthrocentesis

surgical puncture of a joint to remove fluid

synovial fluid tubes

1. plain red top tube for chemical and immunologic evaluation

2. anticoagulant tube (lavender/EDTA) for microscopic examination and cell counts

3. sterile tube (with or without anticoagulant/yellow top) for microbiological studies

lumbar puncture indications (6)

1. infections

2. hemorrhage

3. neurologic disease

4. malignancy

5. tumor

6. treatments

lumbar puncture procedure (adults, children)

1. third or fourth lumbar space

2. fourth or fifth lumbar space

csf tubes

normal csf

clear and colorless

pleocytosis

increased number of cells in csf