heme externship - UA 7.4-7.5

Question 1

which of the following statements about amniotic fluid bilirubin measured by scanning spectrophotometry is true
A. the 410-nm peak is caused by hemoglobin and 450 nm peak from bilirubin
B. baseline correction is not required because a diode array detector is used
C. chloroform extraction is necessary only when meconium is present
D. in normal amniotic fluid, bilirubin increases with gestational age

Answer 1

A.
- measured with a photodiode array

Question 2

which test best correlates with the severity of HDFN
A. Rh antibody titer of the mother
B. lecithin/sphingomyelin ratio
C. amniotic fluid bilirubin
D. urinary estradiol

Answer 2

C.

Question 3

which is the referne method for determining fetal lung maturity
A. human placental lactogen
B. L/S ratio
C. amniotic fluid bilirubin
D. urinary estriol

Answer 3

B.
- a ratio of 2:1 is considered mature
- surfactants formed in lamellar bodies

Question 4

which of the following statements regarding the L/S ratio is true
A. a ratio of 2:1 or greater usually indicates adequate pulmonary surfactant to prevent RDS
B. a ratio of 1.5:1 indicates fetal lung maturity in pregnancies associated with diabetes mellitus
C. sphingomyelin levels increase during the third trimester, causing the L/S ratio to fall slightly
D. a phosphatidyglycerol spot indicates the presence of meconium in the amniotic fluid

Answer 4

A.
- surfactants are disaturate lecithins produced by type II granular pneumocytes
- ratio increases in third trimester

Question 5

which of teh following conditions is most likely to cause a falsely low L/S ratio
A. the presence of PG in amniotic fluid
B. freexing the specimens for one month at -20C
C. centrifuation at 1,000 x g for 10 min
D. maternal diabetes mellitues

Answer 5

C.
- pulmonary surfactants lost in centrifugation at high force
- blood can lower the ratio

Question 6

which of the following statements accurately describes hCG levels in pregnancy
A. levels of hCG rise throughout pregnancy
B. in ectopic pregnancy, serum hCG doubling time is below expected levels
C. molar pregnancies are associates with lower levels than expected for the time of gestation
D. hCG returns to nonpregnant levels within 2 days following delivery, stillbirth or abortion

Answer 6

B.
- usually, levels rise after implantation and peak at weeks 9-12

Question 7

which of the following statements regarding pregnancy testing is true
A. beta-subunits of hCG, TSH, and FSH are identical
B. antibodies against beta-subunit of hCG cross react with LH
C. a false pos result may occur in patients with heterophile antibodies
D. serum should not be used for pregnancy tests because proteins interfere

Answer 7

C.
- alpha- subunit is most similar to TSH and FSH and identicle to LH
- false pos in patients with anti-mouse immunoglobulin antibodies

Question 8

SITUATION: 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 diluted 10-fold and the assay was repeated. The level was found to be grossly elevated. What best explains the situation
A. the wrong specimen was diluted
B. a pipetng error was made in the first analysis
C. antigen excess caused a falsely low result in the undiluted sample
D. an inhibitor of the Ag-Ab reaction was present in the sample

Answer 8

C.
- hook effect
- A molar pregnancy, also known as a hydatidiform mole, is a rare, abnormal pregnancy that occurs when a fertilized egg implants in the uterus and doesn’t develop into a healthy baby

Question 9

which assay result is often approximately 25% below the expected level in pregnancies associated with Down Syndrome
A. serum unconjugated estriol
B. L/S ratio
C. amniotic fluid bilirubin
D. urinary chorionic gonadotropin

Answer 9

A.
- serum unconjugated estriol, hCG, AFP and dimeric inhibin A is the quad screen for Down
- AFP and uE3 (serum unconjugated estriol) are decreased
- inhibin A and hCG are increased

Question 10

which of the following statements about alpha-fetoprotein (AFP) is correct
A. maternal serum may be used to screen for open neural tube defects
B. levels above 4 ng/mL are considered positive
C. elevated levels in amniotic fluid are specific for spinal bifida
D. AFP levels increase in pregnancies associated with Down syndrome

Answer 10

A.

Question 11

first trimester screening for Down syndrome can be performed using which markers
A. AFP and eU3
B. free beta-hCG and pregnancy associate plasma protein A
C. intact hCG and dimeric inhibin A
C. dimeric inhibin B and AFP

Answer 11

B. beta-hCG will be elevated and PAPP-A will be decreased
- AFP is too low to measure in first trimester
- intact hCG and estriol do not distinguish between trisomy 21 and normal pregnancy before 2nd trimester

Question 12

when performing mrker screening tests for Down syndrome, why are results expressed in MoM rather than in concentration
A. concentration is nor normally distributed
B, MoM normalizes for gestational age
C. some tests cannot be reported in mass units
D. mean cannot be determined accurately for these analytes

Answer 12

B.

Question 13

which test for 21 trisomy is not recommended for women who are carrying twins
A. first trimester triple marker screening
B. maternal plasma cell free fetal DNA
C. chorionic villus sampling
D. second trimester quad marker sampling

Answer 13

B.
- changes ratio of fetal:maternal cells since two fetal DNA inputs

Question 14

which statement regarding the fetal fibronectin test is true
A. a positive test is correlated with a low probability of delivery within 14 days
B. the test should bot be performed before week 24 or after the end of week 34
C. the test is performed on amniotic fluid
D> the test is used to identify amniotic fluid after rupture of the fetal membranes

Answer 14

B.
- rules out likelihood of preterm delivery in

Question 15

what is the term for spermatozoa in which the anterior portion of the headpiece is smaller than normal
A. azoospermia
B. microcephaly
C. acrosomal deficiency
D. necroospermia

Answer 15

C.

Question 16

what is the most common cause of male infertility
A. mumps
B. Klinefelter syndrome
C. varicocele
D. malignancy

Answer 16

C.
- hardening of veins that drain the testes causing retarded development of the sperm

Question 17

which of the following values is the lower limit of normal for sperm concentration
A. 15 million/mL
B. 40 million/mL
C. 60 million/mL
D. 100 million/mL

Answer 17

A.
- concentraiton is multiplied by fluid volume to determine count where 40 million is normal per ejaculate

Question 18

which morphological abnormality of sperm is most often associated with varicocele
A. tapering o the head
B. cytoplamic droplet below the neckpiece
C. lengthened neckpiece
D. acrosomal deficiency

Answer 18

A.
- only listed nuclear abnormality which is due to the slow development

Question 19

which of the following stains is used to determine sperm viability
A. eosin Y
B. hematoxylin
C. papanicolaous
D. methylene blue

Answer 19

A.
- eosin Y is used to determine living cells
- others are for morphology

Question 20

which of the following semen analysis results is abnormal
A. volume of 1.0mL
B. liquefaction 40 minutes at room temp
C. pH of 7.6
D. motility 50% progressive movement

Answer 20

A. normal volume is 1.5-5.0 mL

Question 21

which of the following sample collection and processing conditions will lead to inaccurate seminal fluid analysis
A. sample stored at room temp for 1 hour before testing
B. sample collected following coitus
C. sample collected without and anticoagulant
D. sample collected without use of a condom

Answer 21

B. prior ejaculation will alter results

Question 22

when performing a seminal fluid analysis what is the upper limit of normal for WBCs
A. 1 x 10^6/mL
B. 5
C. 10
D. 20

Answer 22

A.

Question 23

which carbohydrate measurement is clinically useful when performing a seminal fluid analysis
A. glucose
B. galactose
.c fructose
D. maltose

Answer 23

C. fructose is the primary nutrient in seminal fluid needed for motility

Question 24

which contition is most often associated wiht gastric ulcers
A. cancer of the stomach
B. H. pylori infection
C. zollinger-ellison syndrome
D. pernicious anemia

Answer 24

B.

Question 25

in which condition is the highest level of serum gastrin usually seen
A. atrophic gastritis
B. pernicious anemia
C. Z-E syndrome
D. cancer of the stomach

Answer 25

C.
- Z-E = gastrin secreting tumor (gastrinoma) from the pancreas

Question 26

in determining free HCl, the gastric fluid is titrated to pH _____
A. 6.5
B. 4.5
C. 3.5
D. 2.0

Answer 26

C.

Question 27

which test can identigy persons with gastrin secreting tumors that do not demonstrate a definitively increased plasma gastrin concentration
A. secretin stimulation
B. pentagastrin
C. cholecystokini-pancreozymin
D. tryipsinogen

Answer 27

A.

Question 28

Which of the following tests would be normal in pancreatic insufficiency
A. secretin stimulation
B. D-xylose absorption
C. 24 hour fecal fat
D. beta-carotene absorption

Answer 28

B.
- xylose differentiates pancreatic insuffiency from malabsorption
- xylose absorbed by small intestine without pancreatic enzymes

Question 29

which of the following is commonly associated with occult blood
A. colon cancer
B. atrophic gastritis
C. pernicious anemia
D. pancreatitis

Answer 29

A.
- blood in feces demonstrates gastrointestinal bleeding

Question 30

which test is most sensitive in detecting persons with chronic pancreatitis
A. fecal trypsin
B. fecal chymotrypsin
C. fecal leastin 1
D. plasma lipase

Answer 30

C.
- Non-invasive indirect indicator of moderate and severe exocrine pancreatic
dysfunction
- chymotrypsin secreted by the pancreas

Question 31

select the most appropriate course of action given these results
- pH: 8.0
- protein: 1+
- glucose, blood, ketone, nitrite, bilirubin neg

A. report results, assuming acceptable quality control
B. check pH with a pH meterbefore reporting
C. perform a turbidimetric protein test, instead of dipstick and report
D. request new specimen

Answer 31

C.
- suspect protein false pos due to alkaline urine

Question 32

given the following results, select the most appropriate course of action
- pH: 8.0
- protein: trace
- ketone: small
- glucose, blood, nitrite: neg
microscopic findings
- RBCs: 0-2 / hpf
- WBCs: 20-50/hpf
- bacteria: large
- crystals: small CaCo3

A. call for a new specimen because urine was contaminated in vitro
B. recheck pH because CaCO3 does not occur at alkaline pH
C. No indication of error is present; results indicate a UTI
D. report all results except bacteria because the nitrite test was negative

Answer 32

C.
- WBCs, bacteria and alkaline characteristic of a UTI (neg nitrite just means that the bacteria doesn’t reduce it or there isn’t sufficient nitrate in the patients diet)

Question 33

SITUATION: a 6mL pediatric urine sample is processed for routine UA in the usual manner. The sediment is prepared by centrifuging all of the urine remaining after performing the biochemical tests. the following results were obtained.
- SG: 1.015
- blood: large
- leukocytes: mod
- protein: 2+
- RBCs: 5-10/hpf
- WBCs: 5-10/hpf
select the most appropriate course of action
A. report these results; blood and protein correlate with microscopic results
B. report biochemical results only; request a new sample for the microscopic
C. request a new sample and report an quantity no sufficient
D. recentrifuge te supernatenatn and repeat microscopic

Answer 33

B.
- due to low volume, microscopic results are unerestimated
- would dilute with saline until sample vol is 12mL and multiply by dilution factor

Question 34

a biochemical profile gives the following results
- creatine 1.4mg/dL
- BUN: 35 mg/dL
- K: 5.5 mmol/L
all other results are normal, and all tests are in control. urine from the patient has an osmolality if 975 mOsm/kg. select most appropriate course of action
A. check fo rhemolysis
B. repeat the BUN, report only if normal
C. repeast serum creatinine, and report only if elevated
D. report results

Answer 34

D.
- BUN:creatinine ratio on par for pre renal failure patient, in that scenario potassium would also be elevated due to reduced renal blood flow and fluid retention

Question 35

SITUATION: a lamellar body count (LBC) was performed on an amniotic fluid sample that was slightly pink within 1 hour of specimen collection. the sample was stored at 4C prior to analysis. the result was 25,000.uL, classified as intermediate risk of RDS. The physician waited 24 hours and collected a new sample that was counted within 2 hours of collection on the same instrument. the LCB count of the new sample was 14,000/uL and the patient was reclassified as a high risk for delivery. Which statement best explains these results

A. loss of lamellar bodies occurred in the second sample because of storage
B. blood caused a falsely elevated result for the first sample
C. the fetal status changed in 24 hours b/c of respiratory illness
D. the difference in counts is the result of day to day physiological and instrument variance

Answer 35

B.
- due to instrumentation, LBC are counted on the hematology analyzer in platelet mode. If blood contaminates the sample, platelets and LBC will be read together and cause a false elevation