What laboratory tests are performed for screening aneuploidy?

The correct choice involves performing specific laboratory tests that are part of the screening process for aneuploidy, particularly in pregnancy. Free β-hCG (beta-human chorionic gonadotropin), PAPP-A (pregnancy-associated plasma protein A), and nuchal translucency measurement are all important components of first-trimester screening for chromosomal abnormalities, including Down syndrome (trisomy 21) and trisomy 18.

Free β-hCG levels are typically elevated in pregnancies affected by certain aneuploidies, while PAPP-A levels are often decreased in these cases. Nuchal translucency, which is an ultrasound measurement of the fluid at the back of the fetus's neck, can also indicate risk for aneuploidy when increased. Together, these tests provide a risk assessment that allows for further diagnostic procedures if necessary, such as chorionic villus sampling or amniocentesis.

The other options listed do not pertain to screening for aneuploidy. Urinary ketones and liver function tests are relevant in the evaluation of other medical conditions, but they do not assess chromosome abnormalities in the fetus. Total protein and serum electrolytes are more general assessments of a patient’s overall health rather than