Ch 16 - Urinalysis Flashcards
why a first-voided morning specimen is often preferred for urinalysis
it is the most concentrated and most accurate sample
what is urea
breakdown of proteins
define micturition
to urinate
normal act of voiding urine
define nocturnal enuresis
inability of pt to control urination at night during sleep
bedwetting
define retention
the inability to empty the bladder
where can you find microorganisms in the urethra?
normally only in the distal urethra and urinary meatus
what is urine composed of
95% water
5% inorganic and organic substances creatinine
inorganic wastes - chloride, sodium, potassium, calcium, magnesium, phosphate, sulfate
organic wastes - urea, uric acid, ammonia,
how much urine does a normal adult excrete
about 700 - 2000 mL of urine per day
define anuria
failure of kidneys to produce urine
define diuresis
secretion and passage of large amounts of urine
define nocturia
excessive voluntary urination at night
define nocturnal enuresis
involuntary bedwetting while asleep
define oliguria
decreased output of urine
below 400 mL output in 24 hours
due to decreased fluid intake, dehydration, profuse perspiration, vomiting, diarrhea, kidney disease
define polyuria
increased output of urine
exceeds 2000 mL output in 24 hours
due to excessive intake of fluids or caffeine which is a mild diuretic, certain drugs, DM, diabetes insipidus, renal disease
purpose of first voided or clean catch sample
first voided for pregnancy - greatest concentration of substances
clean catch for testing bacteria
purpose of 24 hour urine specimen
to test for kidney stone formation and control and prevent new stone formation
used to perform a creatinine clearance test to check kidney function
importance of obtaining a fresh sample for urinalysis
urine sample must be examined within an hour
bacteria will convert urea to ammonia, making it from acidic to alkaline - creating a false positive result on protein test
bacteria will multiply resulting in a cloudy specimen and increase in nitrite
bacteria will eat the glucose if there was any
red blood cells or white blood cells will break down
casts decompose after several hours
describe the physical examination of urine
color: presence of yellow pigment called urochrome, produced by breakdown of hemoglobin normal is straw-yellow to dark amber hemoglobin or blood - red bile pigments - greenish or yellow brown fat or pus - milky
appearance: normally clear, but cloudy due to bacteria, pus, blood, fat, yeast, sperm, mucous threads, fecal contaminants
odor: urine smell, ammonia smell if old, foul smell from UTI, sweet from DM
specific gravity: measures the weight of the urine compared with the weight of an equal volume of distilled water. indicates amount of dissolved substance in urine
SG ranges from 1.003 - 1.030 but is usually between 1.010 - 1.025
list the types of chemical examination of urine
pH: between 4.6 - 8.0 but usually a normal diet results in 6.0; higher pH indicates a bacterial infection
glucose
protein
ketone
bilirubin
urobilinogen
blood
nitrite
leukocytes
describe the microscopic examination of urine
red blood cells
white blood cells
epithelial cells
casts
misc. structures
how to store bottle of reagent strips
59-86F
not refrigerator or freezer
discoloration = bad
define casts
cylindric structures formed in the lumen of the tubules that make the nephron
materials in tubules harden, are flushed out, appear in urine in forms of casts
their presence indicates a disease
hyaline casts
granular casts
fatty casts
waxy casts
cellular casts
rbc casts
wbc casts
epithelial casts
bacterial casts
crystals in urine
type and number depends on pH of urine. abnormal crystals include leucine, tyrosine, cystine, cholesterol. appear commonly in alkaline urine include amorphous phosphate, triple phosphate, calcium phosphate, ammonium urate crystals
glucose in urine
glucose: 160 - 180 mg/mL per 100 mL of blood
proteins in urine
protein: indicates a pathological condition such as renal disease or bacterial infection, glomerular filtration problems but temporary increase in protein can be due to stress or strenuous exercise
ketones in urine
ketone: normal products of fat metabolism, used by muscle tissue as source of energy. Excess will accumulate in tissues and body fluids known as ketosis
bilirubin in urine
bilirubin: released from the breakdown of hemoglobin, transported to liver and excreted into bile, leaves as feces. liver conditions such as gallstones, hepatitis, cirrhosis can cause it to leave in urine yellow brown or greenish with yellow foam when shaken
urobilinogen in urine
urobilinogen: as bilirubin excreted by liver into the intestinal tract, bacteria in intestines will convert it to urobilinogen. 50% is reabsorbed into the body but most is excreted as feces. conditions such as excessive hemolysis, infectious hepatitis, cirrhosis, CHF, infectious mononucleosis can increase urobilinogen in urine
epithelial cells in urine
epithelial cells: squamous epithelial cells - small amounts are normal and renal epithelial cells are from deeper layers so its presence in urine is abnormal
white blood cells in urine
white blood cells: granular, nucleus, round. 1.5 bigger than rbc, 0-8 per HPF is normal. if more may indicate inflammation in genitourinary tract
red blood cells in urine
red blood cells: appear colorless, round, biconcave disks are highly refractile. 0-5 per high power field is normal. if more than may indicate bleeding in urinary tract. rbc cannot be seen if they are hemolyzed - lysed from swelling
mucous threads in urine
normally present in small amounts in urine
long wavy threadlike structures with pointy ends
bacteria in urine
bacteria should not be in urinary tract
presence of more than a few bacteria indicates contamination of specimen during collection or a UTI
yeast cells in urine
smooth refractile bodies with oval shape
yeast cells in female patient urine indicates a vaginal contamination of candida albicans
may also be present in diabetic mellitus patients
parasites in patients
a contaminant from feces or vaginal material
trichomonas vaginalis is a parasite that causes inflammation in vagina
spermatozoa in urine
is normal after intercourse
purpose of rapid urine cultures
quick and efficient, can be done in medical office
assist in UTI diagnosis and effectiveness of antibiotic therapy for UTI
function of urine pregnancy tests
early diagnosis of pregnancy
checks for presence of a hormone called human chorionic gonadotropin for positive reaction using urine and immunoassay reagent strips
human chorionic gonadotropin
HCG is produced by the developing fertilized egg and small amounts are secreted in urine and blood
highest level in plasma when tested during first trimester
serum pregnancy test
radioimmunoassay for HCG in serum of blood
can detect earlier and greater accuracy than urine
diagnose ectopic pregnancy and other abnormalities of embryonic development and gestational diabetes
