Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
35 Cards in this Set
- Front
- Back
|
At what wavelength light is bilirubin absorbance maximal?
A. 150 nm B. 260 nm C. 320 nm D. 450 nm E. 620 nm |
D. 450nm.
The spectrum of visible light goes from approximately 400-700 nm. Colors appear as their distinct entities due to the fact that colored objects absorb the wavelengths of light that do not pertain and reflects those that do. For example, a red object reflects light at the “red” wavelength (~650nm) and absorbs other wavelengths. The yellow-green bilirubin optimally absorbs at 450 nm (roughly the reflectance of indigo). QCCP2, Amniotic fluid bilirubin |
|
|
Which two variables are plotted on a Liley curve?
A. delta OD320 v. hCG B. delta OD450 v. EGA C. EGA v. hCG D. hCG v. delta OD200 E. none of the above |
B. delta OD450 versus EGA.
The absorbance wavelength is plotted on a semilog plot and a straight line drawn from OD550 to OD350. The difference between the actual absorbance of amniotic fluid at OD450nm and the theoretical line is the delta OD450. The value represents the difference in the amniotic fluid between the background and any bilirubin present. The delta OD450 is then plotted against the estimated gestational age (EGA) on a Liley chart. Bilirubin is a surrogate for hemolysis. Plotting values on the chart assists with clinical decision making for either delivery or intrauterine transfusion. QCCP2, Amniotic fluid bilirubin |
|
|
All of the following hormones share a common alpha subunit, except:
A. prolactin B. TSH C. FSH D. LH E. hCG |
A. prolactin.
The common alpha subunit is paired with a unique beta subunit. For this reason, most specific assays are directed against the beta subunit. Prolactin is a single chain polypeptide, similar to growth hormone or placental lactogen. QCCP2, Maternal serum human chorionic gonadotropin |
|
|
Which of the following outcomes in hCG testing is associated most commonly with heterophile antibodies?
A. true positives B. false positives C. true negatives D. false negatives E. it depends |
B. false positives.
The most common cause of false positive hCG is said to be heterophile antibodies. There are a number of ways to deal with false positive results due to heterophile antibodies. Basically, either get rid of the antibodies or run the assay on a machine that is not affected by heterophile antibodies. False negatives in hCG testing may occur with urine tests due to low sensitivity; false negatives are very rare in these kinds of serum tests. QCCP2, hCG |
|
|
At what point in normal gestation does hCG usually reach maximum levels?
A. within the first two weeks after conception B. end of first trimester C. end of second trimester D. end of third trimester E. 2 weeks post-partum |
B. end of first trimester.
The hCG doubles every 2 days up to 1200 mIU/mL, every 3 days up to ~6000 mIU/mL and every 4 days until the peak at the end of the first trimester where it can reach 100,000 mIU/mL. It decays within a few weeks to a plateau of ~10,000 mIU/mL. QCCP2, hCG |
|
|
What's the most common site for ectopic pregnancies?
A. ovary B. fallopian tube C. cornu D. uterus E. abdomen |
B. fallopian tube.
All of the choices are possible sites of fetal implantation, with the vast majority of ectopic pregnancies occurring in the fallopian tube as most fertilization occurs there. Any dysfunction of the tubal ciliary apparatus could lead to implantation. An implantation within the uterus is normal. I hope that you already knew that. QCCP2, hCG in ectopic pregnancy |
|
|
Beyond hCG levels and ultrasound, which of the following tests has been helpful in distinguishing an intrauterine pregnancy from an abnormal pregnancy?
A. serum progesterone B. serum estrogen C. serum inhibin D. computerized tomographic (CT) imaging E. abdominal plain film radiography |
A. serum progesterone.
Serum progesterone levels above 25 ng/mL are almost diagnostic of a normal intrauterine conception, less than 5 ng/mL is consistent with an abnormal pregnancy. QCCP2, hCG in ectopic pregnancy |
|
|
Which of the following is not a part of the so-called “quad test”?
A. hCG B. alpha-fetoprotein C. dimeric inhibin A D. progesterone E. unconjugated estriol |
D. progesterone.
The triple test consists of the hCG, maternal serum alpha fetoprotein (MSAFP), and unconjugated estriol. The addition of dimeric inhibin A to the triple test makes it the quad test. Because inhibin levels are stable throughout the second trimester, it helps to “standardize” the levels of the other tests and improve the sensitivity. QCCP2, Prenatal screening for trisomy and neural tube defects |
|
|
Which of the following patterns is associated with Edwards' syndrome?
A. increased AFP, increased hCG, increased estriol B. decreased AFP, increased hCG, increased estriol C. decreased AFP, decreased hCG, increased estriol D. increased AFP, decreased hCG, decreased estriol E. decreased AFP, decreased hCG, decreased estriol |
E. decreased AFP, decreased hCG, decreased estriol.
Somewhat sensitive, but not very specific for trisomy 18, the triple test is a fairly effective screening tool, but not a good diagnostic test. Amniotic karyotypic analysis can confirm the diagnosis. QCCP2, Prenatal screening for trisomy and neural tube defects |
|
|
Which of the following patterns is associated with neural tube defects?
A. increased AFP, normal hCG, decreased estriol B. increased AFP, increased hCG, increased estriol C. decreased AFP, normal hCG, decreased estriol D. decreased AFP, increased hCG, decreased estriol E. normal AFP, increased hCG, increased estriol |
A. increased AFP, normal hCG, decreased estriol.
Increased AFP (>2 multiples of the mean) should suggest neural tube defect. An elevated AFP should be repeated if done early, otherwise ultrasound is indicated to further workup the patient. Gestational age, multiple gestations, anatomic abnormalities, or fetal demise must be excluded. After that, amniocentesis should be performed to further workup the case. QCCP2, Prenatal screening for trisomy and neural tube defects |
|
|
Which of the following patterns is associated with Down syndrome (trisomy 21)?
A. decreased AFP, decreased hCG, decreased estriol B. decreased AFP, increased hCG, decreased estriol C. increased AFP, increased hCG, increased estriol D. increased AFP, decreased hCG, increased estriol E. decreased AFP, decreased hCG, increased estriol |
B. decreased AFP, increased hCG, decreased estriol.
In addition, inhibin is usually increased in Down syndrome. The mnemonic “It gets ME Down” helps me to remember that both MSAFP and estriol are down in Down syndrome. Like any abnormality in the triple test screening exam, it should be followed up. In this case, high-resolution ultrasound and amniocentesis with karyotyping have been used. QCCP2, Prenatal screening for trisomy and neural tube defects |
|
|
What is the maternal age above which ACOG 2007 guidelines recommend invasive screening?
A. 27 B. 32 C. 35 D. 37 E. 42 |
C. 35.
The same guidelines mandate that all pregnant women are to be offered non-invasive testing. After age 35, which is considered “advanced maternal age,” or in the event of a positive triple test at any age, the option for invasive screening such as amniocentesis, should be offered. QCCP2, Prenatal screening for trisomy and neural tube defects |
|
|
What is the effect typically of increased maternal weight on maternal serum alpha fetoprotein levels?
A. varies with fetal gender B. increased C. decreased D. no change |
C. decreased.
Increased maternal weight can have a dilutional effect on the serum levels of a number of analytes, MSAFP included. As a result, MSAFP levels may be artifactually lower. QCCP2, Prenatal screening for trisomy and neural tube defects |
|
|
Which of the following organs synthesizes dimeric inhibin as seen in maternal serum?
A. fetal gonads B. maternal ovaries C. fetal kidney D. placenta E. maternal liver |
D. placenta.
Elevated in Down syndrome, DIA is produced by the placenta. DIA levels, unlike unconjugated estriol, MSAFP, and hCG remain relatively constant during pregnancy. QCCP2, Prenatal screening for trisomy and neural tube defects |
|
|
All of the following are part of the definition of pre-term labor, except:
A. rupture of membranes B. regular contractions C. prior to 37 weeks D. associated cervical changes E. all of the above are strictly considered to be part of the definition |
A. rupture of membranes.
Premature labor is defined as regular contractions with associated cervical changes prior to 37 weeks of gestation. PPROM-premature labor with premature rupture of membranes is a separate entity. |
|
|
Type II pneumocytes produce surfactant, which is predominantly composed of a mix of phospholipids called lecithin. What is the primary component of lecithin?
A. phosphatidylcholine B. phosphatidylglycerol C. phosphatidylinositol D. phosphatidylethanolamine E. sphingomyelin |
A. phosphatidylcholine.
Lecithin is composed of multiple types of phospholipids, predominant among these is disaturated phosphatidylcholine (DSPC). DSPC levels can be directly measured to assess for fetal lung maturity. QCCP2, Determination of Fetal Lung Maturity |
|
|
During which time frame in gestation is the assessment of fetal lung maturity most necessary?
A. prior to 30 weeks B. 30-34 weeks C. 34-37 weeks D. 37-39 weeks E. after 39 weeks |
C. 34-37 weeks.
Prior to 34 weeks, the fetal lung is almost certainly immature, therefore obviating the need for assessment of lung maturity at that age. Similarly, after 37 weeks, lung maturity is very likely, also eliminating the need for testing. QCCP2, Determination of Fetal Lung Maturity |
|
|
What lecithin:sphingomyelin ratio is considered to be consistent with fetal lung maturity?
A. 1:1 B. 2:1 C. 1:2 D. 5:1 E. 1:5 |
B. 2:1.
2:1 is considered a reliable cutoff for most pregnancies. Typically the lecithin levels rise until the ratio reaches 2:1, which usually occurs around 35 weeks. The chances of developing respiratory distress syndrome are very low, with a ratio of 2:1 or higher. It is important to remember that a number of conditions, such as maternal diabetes, blood, and meconium can affect the interpretation of the L:S ratio. QCCP2, Determination of Fetal Lung Maturity |
|
|
Which of the following analytes can be measured as an indication of lung maturity when confounding factors preclude accurate determination of maturity by L:S
ratios? A. lecithin alone B. phosphatidylinositol C. phosphatidylinositol phosphate D. phosphatidyl glycerol E. diacylglycerol |
D. phosphatidylglycerol.
Since the presence of blood or meconium doesn't inhibit the measurement of phosphatidyl glycerol, which first appears around 36 weeks, it is an excellent surrogate for the lecithin:sphingomyelin ratio. Alternatively, disaturated phosphatidyl choline can also be measured. QCCP2, Determination of Fetal Lung Maturity |
|
|
Which of the following is typically INCREASED in pregnancy?
A. GFR (glomerular filtration rate) B. BUN (blood urea nitrogen) C. creatinine D. urate E. none of the above are typically increased |
A. glomerular filtration rate (GFR).
Perhaps due to an increased plasma volume, the GFR usually increases in pregnancy. As a result the BUN, creatinine, and urate usually decrease. QCCP2, Laboratory Evaluation of Diseases in Pregnancy |
|
|
At which point with all other risks being equal is a mother's risk of thromboembolism the highest?
A. pre-pregnancy B. first trimester C. second trimester D. third trimester E. postpartum |
E. postpartum.
The incidence of thromboembolism such as DVT rises from 1/2000 antepartum to up to 1/700 postpartum. The risk during pregnancy (and immediately postpartum) is much greater than pre-pregnancy. QCCP2, Medical conditions of importance in pregnancy |
|
|
Which of the following autoimmune diseases tends to actually decrease in severity during pregnancy?
A. rheumatoid arthritis B. Graves disease C. myasthenia gravis D. A & B E. A, B, C |
D. A & B.
Pregnancy tends to ameliorate the effects of rheumatoid arthritis and, less reliably, Graves disease. SLE and myasthenia tend to become worse during pregnancy. QCCP2, Medical conditions of importance in pregnancy |
|
|
What is the most common cause of death due to lupus in pregnant women?
A. hypertension B. hypercoagulation C. lupus pneumonitis D. renal failure E. Libman-Sacks endocarditis |
C. lupus pneumonitis.
Pulmonary hemorrhage secondary to lupus pneumonitis is the most common cause of death in pregnant women with SLE. Pregnancy-induced hypertension must be distinguished from a lupus cause of hypertension because the treatments are very different. Thromboembolism and pulmonary embolism are causes of morbidity and mortality in SLE patients, but at a lower rate than pneumonitis. The renal failure associated with lupus is usually irreversible. QCCP2, Medical conditions of importance in pregnancy |
|
|
Which of the following cause Sheehan syndrome?
A. pregnancy-associated pituitary enlargement B. severe blood loss during pregnancy C. thromboembolic disease D. A & B E. A, B, C |
D. A & B.
The vast majority (~90%) of patients have a history of severe postpartum bleeding. In addition to the physiological enlargement of the pituitary during pregnancy, pituitary apoplexy can occur. This is the cause of Sheehan syndrome, which is manifested as lethargy, weakness, amenorrhea, and the inability to lactate. QCCP2, Medical conditions of importance in pregnancy |
|
|
Which of the following is the cause of hyperemesis gravidarum?
A. hypothyroidism B. hyperthyroidism C. high levels of hCG D. high levels of progesterone E. none of the above |
C. high levels of hCG.
Hyperemesis gravidarum is the most common cause of hyperthyroidism in pregnancy. It is thought that very high levels of hCG cause hyperemesis gravidarum. QCCP2, Medical conditions of importance in pregnancy |
|
|
What is the most commonly associated comorbidity of acute fatty liver of pregnancy?
A. pulmonary embolism B. Budd-Chiari syndrome C. hepatic adenoma D. disseminated intravascular coagulation E. cirrhosis |
D. disseminated intravascular coagulation (DIC).
Because DIC is commonly seen with acute fatty liver of pregnancy it is a medical emergency, although somewhat rare it is associated with very high mortality. Acute fatty liver presents late in pregnancy and can be associated with multiple metabolic defects. QCCP2, Medical conditions of importance in pregnancy |
|
|
All of the following are common forms of investigation into recurrent pregnancy loss, except:
A. parental karyotyping B. endometrial biopsy C. lupus anticoagulant testing D. urine drug screen E. thyroid function tests |
D. urine drug screen.
Recurrent pregnancy loss is defined as two or more spontaneous abortions. A number of clinical and laboratory investigations are done in the case of recurrent loss, but urine drug screen is usually not one of them. QCCP2, Recurrent pregnancy loss |
|
|
What type of kinetics does the elimination of most drugs or foreign agents follow?
A. zero order B. first order C. second order D. mixed order E. higher order |
B. first order.
Most drugs are eliminated by first-order kinetics, where the rate is proportional to the concentration of the drug. An exponential decrease in drug concentration occurs with time as the body eliminates a constant proportion of the drug. Zero-order reactions occur at a constant rate, irrespective of drug concentration. The concentration of the drug is much greater than the Km of the enzyme. Notable drugs eliminated by zero-order kinetics are alcohol and high dose phenytoin or salicylates. A secondorder reaction is more complex and the rate is dependent on the product of the concentration of two reactants, while mixed or higher order reactions have a fractional rate constant. QCCP2, Toxicology |
|
|
How many half-lives (with dosing at the half-life) are typically needed to reach a steady state?
A. 1 B. 2 C. 5 D. 10 E. 20 |
C. 5.
After 5 half-lives, a drug dosed at every half-life will reach steady state. It is important to realize that steady state is a fluctuating condition with trough levels prior to dosing and peaks shortly after. QCCP2, Half-life |
|
|
Under which condition is a protein-bound drug usually at its most efficacious?
A. high serum protein levels B. low serum protein levels C. high hydrostatic pressure D. low hydrostatic pressure E. none of the above |
B. low serum protein levels.
Active drug is most commonly the unbound or free form. Any condition that increases the amount of unbound drug, such as decreased protein, a change in pH, etc., can potentially increase the efficacy. QCCP2, Half-life |
|
|
What does a high volume of distribution for a drug imply?
A. high plasma concentration B. strict limitation to the vascular space C. lipophilicity and hydrophobicity D. wide distribution into vascular, extravascular, and adipose tissue E. none of the above |
D. wide distribution into vascular, extravascular, and adipose tissue.
Simply stated, the volume of distribution is how many places in the body a drug can inhabit. A large VD implies that the drug can be in many of these places, while a small one implies the drug is more limited. To express the VD mathematically, divide the dose of the drug by the plasma concentration. QCCP2, Volume of distribution |
|
|
What is the most common modality used in urine testing for drugs of abuse?
A. immunoassay B. mass spectrophotometry C. electrophoresis D. cell culture E. tasting |
A. immunoassay.
Because immunoassay is most commonly used, there is a risk of cross-reaction and false positive results. A positive screen can then be confirmed with a more specific testing modality, such as gas chromatography/mass spectrometry. QCCP2, Drugs of abuse screening |
|
|
Match the drug of abuse with the key metabolite:
A. cocaine B. heroin C. amphetamines D. PCP E. cannibis 1. norepinephrine and phenylacetone 2. hydroxylated and glucoronidated drug forms 3. Δ-9-THC-COOH 4. N-acetylmorphine 5. benzoylecgonine |
A. A-5, B-4, C-1, D-2, E-3.
Cocaine, or benzoylmethyl ecgonine, is very rapidly metabolized to the stable urine-excreted compound, benzoylecgonine. Heroin, or diacetylmorphine, is deacetylated in a stepwise fashion, yielding first a monoacetylated metabolite, N-acetylmorphine, more commonly known as 6-monoacetylated morphine (6-MAM). This is important because it allows the distinction of heroin from morphine or other prescribed opiates. Phencyclidine (PCP) is metabolized by cytochrome P450 oxidase in the liver into glucoronidated and hydroxylated water-soluble forms. Finally, the active ingredient in cannibis, tetrahydrocannibinol (THC), is modified to a water-soluble form, delta-9- THC-COOH. QCCP2, T1.18, Selected Drugs of Abuse |
|
|
What is the physiological basis of acute cocaine-induced chest pain?
A. hypercoagulability and thrombus development B. direct antiplatelet activity C. coronary vasoconstriction D. increased blood pressure E. neurotoxicity |
C. coronary vasoconstriction.
While increased heart rate and blood pressure often accompany cocaine ingestion, it is the ability of the drug to cause coronary vasoconstriction that leads to the chest pain. Prolonged cocaine use can also be atherogenic and cause left ventricular hypertrophy. Usually the end result of vasoconstriction is myocardial infarction. QCCP2, Cocaine |
|
|
Which of the following tests is most significantly affected by cocaine use?
A. myoglobin B. CK-MB C. troponin I D. A & B E. A, B, C |
B. CK-MB.
Both myoglobin and CK-MB are less cardiospecific than troponin in the first place. Secondly, cocaine has an effect on skeletal muscle, which non-specifically elevates myoglobin and CK-MB. Therefore, those two tests (and likely, LDH as well) become even less cardiospecific in patients who use cocaine. QCCP2, Cocaine |
