A 27-year-old primigravida at 32 weeks’ gestation has been diagnosed with complete placenta previa.

(A) Dinitrophenylhydrazine is a laboratory test used to detect phenylketonuria, maple syrup urine disease, and Lowe’s syndrome. (B) Metachromatic stain is a laboratory test that may be used to diagnose Tay-Sachs and other lipid diseases of the central nervous system. (C) The blood serum phenylalanine test is diagnostic of phenylketonuria and can be used for wide-scale screening. (D) A lecithin-sphingomyelin ratio of at least 2:1 is indicative of fetal lung maturity, and survival of the fetus is likely.