calculations
Using a 1:20 dilution and the 5 RBC counting squares of the Neubauer counting chamber, an average of 54 sperm are counted. The sperm concentration is:
a. 54,000,000mL
b. 5,400mL
c. 21,600mL
d. 2,160mL
a. 54,000,000mL
Number of sperm counted x dilution factor/volume x 1000
54 x 20/0.02 mm3 x 1000 mm3/ml = 54,000,000mL
or
Sperm/ml = Sperm counted x 1,000,000.
A 5mL urine specimen is submitted for a routine urinalysis and is analyzed immediately. The SG of the sample is 1.012, and the pH is 6.5. The dry reagent strip blood test is large positive (3+), and the microscopic examination shows 11 to 20 RBCs/HPF. The leukocyte esterase reaction is a small positive (1+), and the microscopic examination shows 0 to 2 WBCs/HPF. What is the most likely cause of these results?
a. myoglobin is present in the sample
b. free hemoglobin is present
c. insufficient volume is causing microscopic results to be underestimated
d. some WBCs have been misidentified as RBCs
c. insufficient volume is causing microscopic results to be underestimated
Microscopic reference ranges are based on 12mL urine. When less urine is used. falsely low results will be obtained unless corrected action is taken. The specimens should have been diluted to 12mL.
which of the following are present in chronic renal failure?
a. blood casts
b. fine granular casts
c. waxy casts
d. fatty casts
c. waxy casts
Because the casts must remain lodged in the tubule long enough for the granular protein matrix to waxify, they are associated with chronic and end-stage renal failure
a. bilirubin
b. cholesterol
c. ammonium biurate
d. calcium oxalate
b. cholesterol
at what pH are ammonium biurate crystals usually found in urine?
a. acid urine only
b. acid or neutral urine
c. neutral or alkaline urine
d. alkaline urine only
d. alkaline urine only
ammonium biurate is often called the "thornapple"
calculate 24hrs creatinine clearance: plasma creatinine 8mg/L; urine creatinine 500mg/L; urine volume 1.5L (urine creatinine x volume) / plasma creatinine 1day = 1440 min; 1L = 1000mL
a. 6.5mL/min
b. 0.75mL/min
c. 65mL/min
d. 85mL/min
c. 65mL/min
500mg x [(1.5L/1day) x (1day/1440min)] =0.52mg/min
0.52mg/min / 8mg/L = 0.065L/min
0.065L/min x 1000mL/L = 65mL/min
a urine sample with a pH of 6.0 produces an abundance of pink sediment after centrifugation that appears as densely packed yellow- to reddish-brown granules under the microscope. The crystals are so dense that no other formed elements can be evaluated. What is the best course of action?
a. request a new urine specimen
b. suspend the sediment in prewarmed saline, and then repeat centrifugation
c. acidify 12ml aliquot with three drops of glacial acedic acid, and heat to 56C for 5min before centrifuging
d. add five drops of 1N HCL to the sediment and examine
b. suspend the sediment in prewarmed saline, and then repeat centrifugation
urates are yellow-brown or reddish-brown granules and form in acid or neutral urine. They often form following the refrigeration of urine and can be dissolved by the addition of warm saline or dilute NaOH.
urine sediment characterized by pyuria with bacterial and WBC casts indicates?
a.nephrotic syndrome
b.pyelonephritis
c.polycystic kidney disease
d.cystitis
b.pyelonephritis
pyelonephritis results from bacterial infection
a. magnesium ammonium phosphate (triple phosphate)
b. leucine
c. ammonium biurate
d. calcium oxalate
a. magnesium ammonium phosphate (triple phosphate)
which of the following crystals is seen commonly in alkaline and neutral urine?
a. calcium oxalate
b. uric acid
c. magnesium ammonium phosphate
d. cholesterol
c. magnesium ammonium phosphate
aka triple phosphate resembling coffin lid
Given the following data, determine the corrected CSF WBC count: CSF values = RBCs:6,000/uL WBCs:150/uL; peripheral blood values = RBCs:4.0x10^6/uL WBCs:5.0x10^3/uL
a. 8/uL
b. 142/uL
c. 120/uL
d. 145/uL
b. 142/uL
corrected WBCs = WBC CSF - [(blood WBC x CSF RBC)/blood RBC)]
=150 - [(5.0x10^3 x 6000)/4.0x10^6)]
=142
Urinalysis of a sample from a patient suspected of having a transfusion reaction reveals small, yellow-brown crystals. Dry reagent strip tests are normal with the exception of a positive blood reaction (moderate) and trace positive protein. The urine is 6.5. What test should be performed to positively identify the crystals?a. confirmatory test for bilirubin
b.cyanide-nitroprusside test
c.polarizing microscopy
d. Prussian blue stain
d. Prussian blue stain
used to detect hemosiderin crystals
the presence of tyrosine and leucine crystals together in urinary sediment usually indicates:
a. renal failure
b. chronic liver disease
c. hemolytic anemia
d. hartnup disease
b. chronic liver disease
together they cause chronic liver disease, usually cirrhosis of the liver.
a. calcium carbonate
b. uric acid
c. ammonium biurate
d. calcium oxalate
c. ammonium biurate
which crystal appears in urine as a long, thin hexagonal plate and is linked to ingestion of large amounts of benzoic acid?
a. cystine
b. hippuric acid
c. oxalic acid
d. uric acid
b. hippuric acid
It results from the metabolism of benzoic acid. It may occur normally as a result of ingestion of vegetables preserved in benzoic acid,
Calculate the creatinine clearance for a patient of average size from the following data: Urine volume: 720 mL for 12 hours, Urine creatinine: 120 mg/dL, Serum creatinine: 1.5 mg/dL
a. 100mL/min
b. 120mL/min
c. 80mL/min
d. 60mL/min
c. 80mL/min
Urine creatine /plasma creatine x urine volume
24hrs = 1440min
at 24hrs: urine volume 1440mL
(120mg/dL x 1440mL) / (1.5mg/dL x 1440min)
120 mL / 1.5 min = 80mL/min
what is the most likely cause of the following CSF results?
CSF glucose 20mg/dL; CSF protein 200mg/dL; CSF lactate 50mg/dL (reference ranges 5-25mg/dL)
a. viral meningitis
b. viral encephalitis
c. cryptococcal meningitis
d. acute bacterial meningitis
d. acute bacterial meningitis
lactate levels rise b/c increased pressure and hypoxia, correlated with bacterial meningitis >35mg/dL
which of the following conditions characterizes acute renal failure and helps differentiate it from chronic renal failure?
a. hyperkalemia
b. hematuria
c. cylindruria
d. proteinuria
a. hyperkalemia
in acute renal failure, reduced glomerular filtration coupled with decreased tubular secretion results in hyperkalemia
a. calcium carbonate
b. uric acid
c. cystine
d. calcium oxalate
d. calcium oxalate
small, yellow needles are seen in the sediment of a urine sample with a pH of 6.0. Which of the following crystals can be ruled out?
a. sulfa crystals
b. bilirubin crystals
c. uric acid crystals
d. cholesterol crystals
d. cholesterol crystals
cholesterol crystals colorless rectangles plates that have notched corners. "stair-case" arrangement
calculate creatinine clearance: serum creatinine = 1.2mg/dL, urine creatinine = 100 mg/dL, urine volume = 1.4L/day, body surface area = 1.80 m^2
a. 47 mL/min
b. 78 mL/min
c. 100 mL/min
d. 116 mL/min
b. 78 mL/min
urine creatinine/plasma creatinine x urine volume x (1.73/body surface volume)
100mg/dL / 1.2mg/dL x 1.4L/day x (1 day/1440min) x (1.73/1.8) = 78 mL/min
A pregnant woman was seen by her physician, who suspected a molar pregnancy. An hCG test was ordered, and hCG levels were found to be low. The sample was undiluted 10-fold and the assay was repeated. The level was found to be grossly elevated. What best explains this situation?
a. the wrong specimen diluted
b. a pipetting error was made in the first analysis
c. antigen excess caused a falsely low result in the undiluted sample
d. an inhibitor of the antigen-antibody reaction was present in the sample
c. antigen excess caused a falsely low result in the undiluted sample
"hook effect" In extreme antigen excess, the hCG saturated both antibodies, preventing sandwich formation. This results in measurement of falsely low levels of hCG.
which of the following conditions is associated with the greatest proteinuria?
a. acute glomerulonephritis
b. chronic glomerulonephritis
c. nephrotic syndrome
d. acute pyelonephritis
c. nephrotic syndrome
a. calcium carbonate
b. uric acid
c. cystine
d. tyrosine
a. calcium carbonate
how can hexagonal uric acid crystals be distinguished from cystine crystals?
a. cystine is insoluble in hydrochloric acid, but uric acid is soluble
b. cystine gives a positive nitroprusside test after reduction with sodium cyanide
c. cystine crystals are more highly pigmented
d. cystine crystals form at neutral or alkaline pH, uric acid forms at neutral to acidic pH
b. cystine gives a positive nitroprusside test after reduction with sodium cyanide
cystine crystals are colorless, whereas uric acid crystals are pigmented (yellow, reddish brown). Cystine is reduced by sodium cyanide forms cysteine. Cysteine reacts with nitroprusside to form a red color.