7.4 Amniotic, Gastrointestinal, and Seminal Fluids Flashcards
Which of the following statements about amniotic fluid bilirubin measured by scanning spectrophotometry is true?
The 410-nm peak is caused by hemoglobin and the 450-nm peak is caused by bilirubin
Which test best correlates with the severity of hemolytic disease of the fetus and newborn (HDFN)?
Amniotic fluid bilirubin
Which is the reference method for determining fetal lung maturity (FLM)?
L/S ratio
Which of the following statements regarding the L/S ratio is true?
A ratio of 2:1 or greater usually indicates adequate pulmonary surfactant to prevent RDS
Which of the following conditions is most likely to cause a falsely low L/S ratio?
Centrifugation at 1,000 × g for 10 minutes
Which of the following statements accurately describes human chorionic gonadotropin (hCG) levels in pregnancy?
In ectopic pregnancy, serum hCG doubling time is below expected levels
Which of the following statements regarding pregnancy testing is true?
A false-positive result may occur in patients with heterophile antibodies
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 this situation?
Antigen excess caused a falsely low result in the undiluted sample
Which assay result is often approximately 25% below the expected level in pregnancies associated with Down syndrome?
Serum unconjugated estriol
Which of the following statements about alpha fetoprotein (AFP) is correct?
Maternal serum may be used to screen for open neural tube defects
First-trimester screening for Down syndrome can be performed using which markers?
Free β hCG and pregnancy-associated plasma protein A
When performing marker screening tests for Down syndrome, why are results
expressed in multiples of the median (MoM), rather than in concentration?
MoM normalizes for gestational age
Which test for 21 trisomy is not recommended for women who are carrying twins?
Maternal plasma cell free fetal DNA
Which statement regarding the fetal fibronectin test is true?
The test should not be performed before week 24 or after the end of week 34
What is the term for spermatozoa in which the anterior portion of the headpiece is smaller than normal?
Acrosomal deficiency
What is the most common cause of male infertility?
Varicocele
Which of the following values is the lower limit of normal for sperm concentration?
15 million per milliliter
Which morphological abnormality of sperm is most often associated with varicocele?
Tapering of the head
Which of the following stains is used to determine sperm viability?
Eosin Y
Which of the following semen analysis results is abnormal?
Volume 1.0 mL
Which of the following sample collection and processing conditions will lead to inaccurate seminal fluid analysis results?
Sample collected following coitus
When performing a seminal fluid analysis, what is the upper limit of normal for WBCs?
1 × 10^6/mL
Which carbohydrate measurement is clinically useful when performing a seminal fluid analysis?
Fructose
Which condition is most often associated with gastric ulcers?
Helicobacter pylori infection
In which condition is the highest level of serum gastrin usually seen?
Z-E syndrome
In determining free HCl, the gastric fluid is titrated to pH ______.
3.5
Which test can identify persons with gastrin-secreting tumors that do not demonstrate a definitively increased plasma gastrin concentration?
Secretin stimulation
Which of the following tests would be normal in pancreatic insufficiency?
D-Xylose absorption
Which of the following is commonly associated with occult blood?
Colon cancer
Which test is most sensitive in detecting persons with chronic pancreatitis?
Fecal elastin-1
