Urinalysis

Question 1

What are the parts to a urinalysis?

Answer 1

physical properties (clarity, color, volume, foam, odor, specific gravity), chemical properties (pH, proteinuria, hematuria, glycosuria, chemical properties (cells, casts, and crystals)

Question 2

foam characteristics

Answer 2

abundant and vivid yellow is bilirubin; white foam is albumin or proteinuria.

Question 3

What does ammonia smell suggest in urine?

Answer 3

if urine is fresh may suggest infection

Question 4

What is a normal specific gravity for urine and what instruments are used to measure it?

Answer 4

1.003-1.035 is normal. measure with an aurinometer, refractometer, or dipstick

Question 5

Normal pH of urine

Answer 5

4.5-8. Usually around 6.

Question 6

What does elevated urine pH suggest?

Answer 6

either infection with urease producing bacteria, history of emesis (lost too much acid- kidney will try to shed bicarb), or distal renal tubular acidosis

Question 7

What does low urine pH suggest?

Answer 7

hx of diarrhea (pooping out bicarb), starving (protein metab products), diabetes, some resp diseases, pts who eat excessive amts of meat

Question 8

How do you measure urine protein?

Answer 8

dipstick or sulfosalicylic acid testing. dipstick only tests albumin and may miss bence jones, light chains, and other globulin proteins. grading of the sulfosalicylic acid test ranges from negative (no turbitidy) to 4+ (clumps of protein)

Question 9

Hematuria chemical tests: what is measured, how, what else must be done?

Answer 9

dipstick test for hemoglobin, myoglobin, or blood in the urine. A positive urine dipstick doesn’t mean that RBCs are necessarily being filtered at the glomerulus- this determination must be made through a microscopic exam.

Question 10

What are some cases where you might see glycosuria?

Answer 10

DM, renal tubualr disorders, excess sugar loads, stress, and pregnancy

Question 11

What is normal for RBCs on microscopic exam?

Answer 11

less than 5 RBCs/HPF (HPF= high power field). most ppl have 0-2.

Question 12

What is normal for WBCs on microscopic exam? What do high levels suggest?

Answer 12

normal is less than 5/hpf. women have more than men due to urinary contamination. high whenever there is inflammation in the urinary tract: infection, glomerulonephritis, interstitial nephritis.

Question 13

renal tubular epithelial cells

Answer 13

sign of significant tubular damage if seen in great number. the are oval or triangular with large eccentric nuclei.

Question 14

Waxy casts

Answer 14

seen in pts with advanced chronic kidney disease and renal amyloidosis. represent the final stage of cellular degeneration after prolonged renal stasis. Wider than hyaline cases, easier to visualize due to sharper outlines, and more refractile. Fissues on the sides and blunted ends.

Question 15

Significance of RBC casts

Answer 15

if you see true RBC casts (and not just RBC clumps), this usually suggests glomerular disease and localizes the bleeding to the kidney.

Question 16

granular casts

Answer 16

from brakedonw of cells within casts or from adjacent renal tubular cells or from plasma proteins. May indicate acute tubular necrosis (muddy brown casts), or exercise, vol depletion, fever.

Question 17

What are the acidic crystals?

Answer 17

uric acid, calcium oxalate, cysteine

Question 18

morphology of the acidic crystals

Answer 18

uric: square/diamond shaped
calcium oxalate: squares with xes in them
cystine: hexagons

Question 19

alkaline crystals (name, morphology, what they indicate)

Answer 19

struvite. look like coffin lids. aka triple phosphate crystals. formed only when urease producing bacteria are present.

Question 20

amorphous phosophates

Answer 20

made of phsophates when urine pH is above 6.5 and of urates when urine pH is relatively low.

Question 21

lipiduria: what it suggests and how it presents

Answer 21

often seen in nephrotic syndromes. mya present as free fat droplets, encased in renal tubular epithelial cells (oval fat bodies), or as a maltese cross in polarized light.