Q What diagnosis code would I use for an abnormal quad test?
A The quad test is an “enhanced prenatal screening test” for Down syndrome, trisomy 18, and neural tube defects that is performed between the 15th and 20th week of gestation. It measures 4 substances in the mother’s blood that come from the developing fetus and placenta: alpha-fetoprotein, human chorionic gonadotropin (hCG), estriol, and inhibin-A (which is not included in the routine triple screen).
A positive result simply places the patient at higher risk for having a baby with one of the indicated conditions—it does not diagnose the child with anything. Unless the patient has a family history of Down syndrome or neural tube defects, the correct ICD-9 code is V28.8 (other antenatal screening). If there is a relevant family history, use V23.49 (pregnancy with other poor obstetric history) along with either V18.4 (family history of mental retardation) or V19.5 (family history of congenital anomalies).
For positive screening tests, use 655.13 (known or suspected chromosomal abnormality in fetus) or 796.5 (abnormal finding on antenatal screening), because you do not yet have a definitive diagnosis.
If a problem with the fetus is confirmed through additional testing, you will use the code for the diagnosed condition for the rest of the pregnancy.