Urinalysis Flashcards
Who wrote a book on uroscopy? In what century?
Hippocrates, 5th century BCE
Who discovered albuminuria?
Frederik Dekker
Why are UA’s favored?
Urine is easy to collect & urine contains many info about the body’s metabolic functions
What are the two types of nephrons?
cortical
juxtamedullary
Which nephron is responsible for concentration of urine?
juxtamedullary
The cortical nephron is responsible for what?
85% of all nephrons
removal of waste products & reabsorption of nutrients
The functions of the nephrons are controlled by?
renal blood flow
glomerular filtration
tubular reabsorption
tubular secretion
What is the average daily urine output?
1200mL
What are the organic constituents of urine?
urea, creatinine, uric acid
What are the inorganic constituents of urine?
chloride, sodium, potassium, water
What is the normal range of urine output?
600-2000mL
What is the value for oliguria?
<400mL/day
What is the value for polyuria?
> 2.5L/day
Which diabetes has high specific gravity? Why?
diabetes mellitus
due to inc glucose content
Describe Diabetes insipidus…
dec ADH with low specific gravity
When is proteinuria clinically significant?
30mg/dL or 300mg/24hrs
What is the major serum protein found in urine?
albumin
What is prerenal proteinuria caused by?
conditions that affect plasma prior to it reaching the kidneys
What is the renal threshold for glucose?
160-180mg/dL
What is the temp urine should be refrigerated?
2-8 degrees Celsius
What are the type of urine specimen is the most commonly received?
random specimen
Which type of urine specimen is essential for preventing false-negative pregnancy tests?
first-morning
What is the most commonly requested test on a catheterized specimen?
bacterial culture
How is a midstream clean catch a better alternative to the catheterized specimen?
It is safer, less traumatic & less contaminated
What is the term that describes urine collected by external introduction of a needle through the abdomen into the bladder & can also be used for cytologic examination?
suprapubic aspiration
What are the methods of collection for prostatitis?
3-glass
pre & post massage test
What is the amt of urine needed for drug testing?
35-45mL
What is the yellow color of urine caused by?
a pigment, urochrome
What other pigments are found in urine?
uroerythrin & urobilin
What is significant about urine samples that contain abnormal pigment bilirubin?
the urine may have yellow foam when the specimen is shook which also could be mistaken for phenazopyridine
What could fresh brown urine containing blood indicate?
the presence of methemoglobin and glomerular bleeding
What is different about urine specimen that has RBCs vs. hemoglobin?
urine + RBCs = red and cloudy
urine + Hgb = red and clear
How do you determine hemoglobinuria vs. myoglobinuria?
by examining the patient’s plasma
hemo - red plasma
myo - doesn’t change plasma color
What are medications that can cause brown/black urine?
levodopa
methyldopa
phenol derivatives
metronidazole
Besides medication, what else causes black urine?
melanin
homogentisic acid
What produces a white precipitate in urine with alkaline pH?
amorphous phosphates & carbonates
What produces a pink brickish precipitate in urine with acidic pH?
amorphous urates due to uroerythrin
What is known as the density of a solution compared with the density of a similar volume of distilled water @ a similar temperature?
specific gravity
What is the purpose of determining specific gravity?
to determine the patient’s hydration level
What are the specific gravity values for…
isosthenuric
hyposthenuric
hypersthenuric
isosthenuric - 1.010
hyposthenuric - below 1.010
hypersthenuric - above 1.010
What does a refractometer do?
determines the concentration of dissolved particles in a specimen by measuring refractive index
In a refractometer, what determines the angle at which the light beam enters the prism?
the concentration of the specimen
What methods of obtaining specific gravity?
refractometer
chemical reagent strips
osmolality
The reagent strip reaction is based on the change in….
pKa
Where can abnormally high specific gravity values been seen in?
intravenous pyelogram
ppl receiving dextran (plasma expanders)
What is prerenal proteinuria?
protein in urine caused by plasma conditions not renal conditions
What is an example of inc serum protein levels?
bence jones proteins due to multiple myeloma
What is orthostatic proteinuria?
a persistent benign proteinuria in young adults
What is the most frequently performed chemical test analysis on urine?
glucose
What urine substance provides a rapid screening test for UTI?
nitrite
What is the third part of routine urinalysis? What does it detect?
microscopic examination, insoluble materials, least standardized & most time consuming
(RBCs, WBCs, epithelial cells, casts, bacteria, yeast, parasites, mucus, spermatozoa, crystals and artifacts)
What type of ppl will always require a microscopic examination?
pregnant women pediatric geriatric immunocompromised renal patients
How do you get rid of crystals in urine?
put it to room temp (37 C)
Describe centrifugation…
5 minutes at RCF of 400 instead of RPM
What are the two methods to place your centrifuged sample on a slide?
Glass slide method (most common)
commercial systems
What is the most frequent stain used in urinalysis? What does it show?
sternheimer-malbin stain, (crystal violet) (sedi-stain, KOVA), shows WBCs, epithelial cells & casts
What does toluidine blue stain?
WBCs vs. renal tubular epithelial cells
What are the lipid stains?
Oil Red O & Sudan III
What do gram stains help you identify?
bacteria
What does Hansel stain help you identify?
transplant rejection (eosinophils)
What stain is used to identify iron?
Prussian blue
When do dysmorphic RBCs appear?
after strenuous exercise or glomerular bleeding
How do glitter cells form?
A WBC that swells in hypotonic urine
What is an increase in WBCs in urine?
pyuria
What are the three types of epithelia cells?
squamous
transitional
renal tubular epithelial (RTE)
What are the origins of the epithelial cells?
squamous- vagina, urethra
transitional - bladder, renal pelvis, calyces, ureters, upper male urethra
RTE- renal tubules
What is the significance of clue cells?
squamous cells with bacteria attached, shows gardnerella vaginalis infection
What RTE cells are the largest?
RTE cells from the PCT
What are Oval Fat bodies?
RTE cells with lipids
What determines cholesterol formation in cell?
using polarized light to view maltese cross formation
In severe infections, how does yeast appear?
mycelial (branched)
What is the most common parasite in urine?
trichomonas vaginalis
What is a major component of mucus & casts?
Tamm-Horsfall protein
What elements are unique to the kidney?
casts
What is the most frequently seen cast?
hyaline cast
What cast is seen with oval fat bodies?
fatty cast
What creates the graininess inside your granular casts?
lysosomes
What type of crystals are seen in gout?
uric acid
What crystal is shaped like a coffin lid?
triple phosphate
What crystal is shaped like a thorny apple?
ammonium biurate
What crystal are perfectly 6-sided?
cystine
What crystals are associated with liver disorders?
tyrosine
leucine
bilirubin
