intro to labs Flashcards
what is a urinalysis comprised of?
macroscopic/microscopic, examination, dipstick and specialty testing
what must every label collection container have?
at least 2 patient identifiers with a sterile container
what is the preferred method for collecting a urine sample?
clean catch technique (necessary for UTI) , mid stream preferable
when is the best time to collect urine?
in the morning because its when it is most concentrated, preferred particularly for protein and specific gravity
A urine sample should be tested with in how many hours?
2 hour otherwise results will not be accurate
up to 4 hours if refrigerated
when do you send a urine for culture
Only send if patient has signs and symptoms of infection or an abnormal U/A
A urinary infection is classified as a bacterial count of?
> 100,00 colonies
or
10,000 colonies if symptomatic, immunosuppressed or antibiotic treated
what happens if you get back a mixed bacterial count <10,000
would be contaminated
when would it be normal to see RBC on microscopic U/A?
after exertion, trauma, fever, menstruation
when would RBC be abnormal on microscopic U/A?
UTI, glomerulonephritis, necrosis, tumors, stones, coagulopathies
when would you see WBC on a U/A
UTI or inflammation
when would you see squamous cells on U/A?
contamination
when would you see renal tubular cells?
acute tubular necrosis, nephrotic syndrome
When would you see bacteria in a U/A
UTI
what do fat bodies on a U/A tell you?
Nephrotic syndrome, you will see maltese cross appearance
what are casts?
- Unique to kidneys – formed in lumen of DCT and collecting duct
- The shape represents molds of the renal tubule from which they arise
what are hyaline casts?
- Tamm-Horsfall protein (small amt is normal)
* Multiple casts-assoc w/ all renal dz, essential HTN, nephrotic syndrome
WBC casts
renal parenchymal infx, MC pyelonephritis
RBC casts
Hydronephrosis, infections
granular casts
- Formed by breakdown products of cellular casts and immunoglobulins
- Deeply pigmented (muddy brown) = acute tubular necrosis
Fatty casts
•Leakage of lipoproteins through glomerular filter (nephrotic syndrome)
When there is protein in the urine what is that indicative of?
renal disease
proteins can be either albumin or globulins (bence-jones are associated with multiple myeloma)
small amounts in DM and HTN may be first sign of CKD
what does the presence of bilirubin in the urine tell you?
early sign of biliary obstruction
Urobilinogen?
formed by bacterial conversion of conjugated bilirubin in intestine
Most sensitive test to determine impaired liver function
One of the earliest signs of liver disease and hemolytic disorders
what causes hemoglobinuria?
burns, transfusions rxns, chemical agents, malaria, post-op hemolysis
what causes hematuria?
UTI, stones, tumor, glomerulo/pyelonephritis, kidney, trauma, PCKD, leukimia
What is cherry red blood with out RBC and blood serum levels of muscle destruction?
myoglobinuria
glucose in urine?
should be non, present when serum glucose is 160-180mg/dl (renal threshold)
increased in diabetes, cushings, brain injury
what causes ketones in the Urine?
there should be none but they result from the metabolism of fatty acids
used to screen for DKA
Increased in starvation, fasting, high fat diets, prolonged vomiting
What does the presence of leukocyte esterases in urine tell you
marker of infection
needs to be verified with microscope for WBC
what does nitirites in urine tell us?
detects bacteria
present in setting of UTI’s- needs culture
Azo dye and bilirubin will result in false positive
neg. test does not rule out UTI
what is the range of urine pH?
5-9, usually around 6
what is the cause acidic urine?
E. coli which is also MCC of UTI
respiratory acidosis, K deficiency
what is the cause of alkaline urine?
Klebsiella causing UTI, renal tubular acidosis, chronic renal failure, metabolic acidosis, respiratory alkalosis
what is specific gravity?
kidney’s ability to concentrate urine
measures the density of dissolved chemicals
Osmolality
what causes red urine
hematuria, porphyrins, pyridium, food color, beets
what causes yellow brown urine
bilirubin
what causes brown black urine
melanin, methyldopa
what causes bright orange urine
rifampin
what causes blue or green urine?
dyes or meds
what is microalbumin in urine?
small increase in urinary excretion of albumin that is too small to be detected in conventional U/A
screening tool to assess risk of early diabetic/HTN nephropathy
why is a 24 hour urine useful and what are its indications?
more accurate information on measurement
Indicated for: CrCl, stone analysis, hormonal dz of adrenal glands, quantify proteinuria
what is BUN
urea is formed in the liver as an end product of protein metabolism and digestion
As kidney function decreases BUN level rises
Its an indirect measurement of renal/liver function and GFR
what is creatinine
More specific and sensitive indicator of kidney function than BUN alone
production is constant as long as muscle mass remain constant
not affected by BUN
As Kidney function decreases Creatinine levels rise
what is KUB used as a diagnostic test for?
demonstrates size, shape, location and malformation of kidneys and bladder
Initial study to dx intra-abdominal gas patterns, soft tissue mass, ruptured bowel
what is IV pyelography?
radioopaque contrast to visualize kidneys, pelvis, ureters, bladder
what are the indications for IV pyelography?
persistent pain, hematuria, trauma, obstruction tumor
Images will be obtained over 30min showing passage of dye through renal system
How can you tell if renal artery is blocked with IV pyelography?
dye will not enter the renal system, if there is a partial block will take longer to pass
what is cystoscopy and what are the benefits of it
endoscope used to assess urethra, bladder and lower ureters and it allows you to take biopsies.
what is urea
Major nitrogen containing product of protein metabolism
what is creatinine
spontaneous breakdown product of muscle energy metabolism
what is creatinine clearance?
measures the rate at which the kidney clear creatinine from the blood
what is anuria?
lack of urine output <50ml per day
what are casts?
Protein aggregates, outlined in the shape of renal tubules and excreted into the urine; the matrix is the Tamm-Horsfall protein (seen under the microscope)
what is oligouria?
decreased urine output <400ml per day
what is albuminuria?
albumin in urine but there should not be any
what is uremia?
High BUN used interchangeably with Azotemia
what is Nephritis?
Inflammation of the kidney with focal or diffuse proliferation or destructive processes that may involve the glomerulus, tubule, or interstitial renal tissue. Hematuria
what is glomerulonephritis
nephritis accompanied by inflammation of the capillary loops in the glomeruli of the kidney.
Occurs in the acute, sub acute and chronic forms
what is nephrotic syndrome?
general name for a group of disease involving increased glomerular permeability characterized by massive proteinuria, lipiduria, edema, hypoalbuminemia, hyperlipidemia
what is hemodialysis
The exogenous removal of certain elements from the blood by virtue of the difference in the rates of their diffusion through a semi-permeable membrane (for example, by means of a hemodialysis filter) → for kidney failure
How is hemodialysis done?
done through IV or Fistula-MC
3x/week for 3-4 hours
what is peritoneal dialysis?
Hemodialysis through the peritoneum, the dialyzing solution being introduced into and removed from the peritoneal cavity as either a continuous or an intermittent procedure
How is peritoneal dialysis done?
- Can be done at home; noninvasive; not as effective as hemodialysis
- 4-5 times/ day
