The levels may indicate increased risk for certain conditions or may be benign: AFP UE3 hCG Associated conditions low low high Down syndrome low low low trisomy 18 (Edward's syndrome) high n/a n/a neural tube defects (like spina bifida that may have associated increased levels of acetylcholinesterase in the amnionic fluid), omphalocele, gastroschisis, multiple gestation (like twins or<unk> ts), or an underestimation of gestational age. An estimated risk is calculated and adjusted for the expectant mother's age; if she's diabetic; if she's having twins or other multiples, and the gestational age of the fetus. Weight and ethnicity may also be used in adjustments. Many of these factors affect the levels of the substances being measured and the interpretation of the results: * As maternal weight increases, MSAFP level decreases * African-American women have MSAFP levels that are 10-15% higher than those of Caucasian women for unknown reasons * Women with insulin-dependent diabetes mellitus have MSAFP levels that are 20% lower than the rest of the population * Having multiple gestations, such as twins, increases MSAFP because each fetus secretes its own AFP * Incorrect estimation of gestational age is the most common cause of abnormal MSAFP levels The test is for screening, not for diagnosis, and does not have nearly the same predictive power of amniocentesis or chorionic villus sampling. The screening test carries a much lower risk to the fetus, however, and in conjunction with the age-related risk of the patient it is useful to help determine the need for more invasive tests.
Triple test
Odd Man Out test
Glucose test
GALS screen
Glucose tolerance test
Peanut butter test
Ham test
Bolton analysis