Sorted By Test Name - Mayo Medical Laboratories

9804
FLEC
9243
growth factor-binding protein-4 (IGFBP-4), dramatically reducing IGFBP-4 affinity for IGF1 and IGF2,
thereby regulating the availability of these growth factors at the tissue level. PAPP-A is highly expressed
in first-trimester trophoblasts, participating in regulation of fetal growth. Levels in maternal serum
increase throughout pregnancy. Low PAPP-A levels before the 14th week of gestation are associated with
an increased risk for Down syndrome and trisomy 18. Nuchal translucency (NT): The NT measurement,
an ultrasound marker, is obtained by measuring the fluid-filled space within the nuchal region (back of the
neck) of the fetus. While fetal NT measurements obtained by ultrasonography increase in normal
pregnancies with advancing gestational age, Down syndrome fetuses have larger NT measurements than
gestational age-matched normal fetuses. Increased fetal NT measurements can therefore serve as an
indicator of an increased risk for Down syndrome.
Useful For: Prenatal screening for Down syndrome (nuchal translucency, pregnancy-associated plasma
protein A, human chorionic gonadotropin) and trisomy 18 (pregnancy-associated plasma protein A,
human chorionic gonadotropin)
Interpretation: Screen-Negative: A screen-negative result indicates that the calculated screen risk is
below the established cutoff of 1/230 for Down syndrome and 1/100 for trisomy 18. A negative screen
does not guarantee the absence of trisomy 18 or Down syndrome. Screen-negative results typically do not
warrant further evaluation. Screen-Positive: When a Down syndrome risk cutoff of 1/230 is used for
follow-up, the combination of maternal age, pregnancy-associated plasma protein A, human chorionic
gonadotropin, and nuchal translucency has an overall detection rate of approximately 85% with a
false-positive rate of 5% to 10%. In practice, both the detection rate and false-positive rate increase with
age, thus detection and positive rates will vary depending on the age distribution of the screening
population.
Reference Values:
DOWN SYNDROME
Calculated screen risks or =1/230 are reported as screen positive.
TRISOMY 18
Calculated screen risks or =1/100 are reported as screen positive. A numeric risk for trisomy 18 risk is provided with
positive results on non-diabetic, non-twin pregnancies.
An interpretive report will be provided.
Clinical References: 1. Malone FD, Canick JA, Ball RH, et al: First-trimester or second-trimester
screening, or both, for Down's syndrome. N Engl J Med 2005 Nov 10;353(19):2001-2011 2. Screening for
fetal chromosomal abnormalities. ACOG Practice Bulletin No. 77. American College of Obstetricians and
Gynecologists. Obstet Gynecol 2007;109:217–27 3. Wald NJ, Rodeck C, Hackshaw AK, Rudnicka A:
SURUSS in Perspective. Semin Perinatol 2005;29:225-235
Fite-Faraco Stain
Useful For: Staining method for acid-fast organisms.
Reference Values:
The laboratory will provide a pathology consultation and stained slide.
Flecainide, Serum
Clinical Information: Flecainide (Tambocor) is a class I cardiac antiarrhythmic agent with
electrophysiologic properties similar to lidocaine, quinidine, procainamide, and tocainide. Flecainide
produces a dose-related decrease in intracardiac conduction in all parts of the heart, with the greatest
effect on the His-Purkinje system. Atrial effects are limited. Flecainide causes a dose-related and plasma
concentration-related decrease in single and multiple premature ventricular contractions and can suppress
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