Build a foundation for coding genetic testing and screening in obstetrics and maternal fetal medicine

By Lori-Lynne A. Webb, CPC, CCS-P, CCP, CHDA, COBGC

Genetic testing and screening in obstetrics and maternal fetal medicine is one of the fastest moving fields in medical science.
Genetic screening is often used to detect abnormal genes or possible fetal anomalies during antepartum care. Providers use a wide range of screening tests to detect disorders prior to birth. Genetic tests during pregnancy are used to screen for or to detect specific inherited disorder in the unborn baby.
As we move toward ICD-10, coders must possess a strong understanding of basic anatomy and physiology. Antenatal genetic testing and screening is an important part of this training and education.
Types of genetic testing
Physicians perform the most common antenatal genetic testing using non-invasive methods such as a simple blood draw or by using ultrasound as a visual form of genetic screening. Physicians can also use invasive procedures such as amniocentesis or chorionic villus sampling.
Antenatal screening is sometimes considered controversial, but providers always offer screening to the patient and only perform it with the consent of the pregnant woman.
Some patients may request screening be performed prior to a pregnancy to determine if either parent (prospective mother or father) carries a faulty genetic trait. In some cases if both parents carry a specific faulty gene the chance of the baby inheriting that genetic trait goes up substantially. Antenatal chromosomal screening and diagnostic testing is usually performed within the first and second trimester of the pregnancy.
The overall goal of maternal blood testing, (also known as maternal serum blood screening) is to:
  • Identify as many abnormal fetuses as possible
  • Minimize the number of normal pregnancies with abnormal test results (false positives)
Genetic testing also provides the physician a way to determine chromosomal abnormalities in the fetus. This genetic testing targets specific DNA in the fetus. These tests determine whether the fetus has too many chromosomes or an aberration within the chromosomes.
If the baby has an extra chromosome of the very big or gene-rich chromosomes, an early miscarriage may result.
If the fetus has extra chromosomes, the baby may have serious problems or specific chromosomal conditions such as:
  • Trisomy 21, also known as Down syndrome
  • Trisomy 13 also known as Patau’s syndrome
  • Trisomy 18, known as Edwards’ syndrome
These are only a few of the genetic conditions that can be found with prenatal genetic testing.
Types of genetic tests
The most common genetic blood tests are the:
  • Quad screens, which include
    • Maternal serum alpha-fetoprotein (MSAFP) (CPT ® code 82105)
    • Human chorionic gonadotropin (hCG) (CPT code 84702 quantitative)
    • Estriol (CPT code 82677)
    • Inhibin A (CPT code 86336)
  •  MaterniT21 Panel (multi-code genetic testing)
The cost to the patient for genetic screening and testing can vary depending upon the laboratory that is performing the tests. Not all insurance carriers will cover this type of testing, and some insurers require “medical necessity” before covering any type of genetic screening. Pre-authorization from the insurance carrier may be necessary.
Quad screen
The quad screen test is comprised of four separate lab tests that measure four different proteins found in the maternal blood. These proteins actually pass from the fetus or the placenta into the maternal blood stream:
  • Alpha fetoprotein (AFP)
  • Human chorionic gonadotropin (HCG)
  • Unconjugated estriol (uE3)
  • Inhibin A
By testing for and screening of these specific proteins, the provider can evaluate the likelihood that the fetus will be at risk of developing any of the following conditions:
 Down syndrome (Trisomy 21)—a genetic condition that causes lifelong impairments in mental and social development, as well as various physical concerns.
  • Edwards syndrome (Trisomy 18)—a genetic condition that causes severe developmental delays and is often fatal by age 1.
  • Spina bifida—a serious birth defect that occurs when the tissue surrounding a baby's developing spinal cord doesn't close properly and can lead to severe physical and mental disabilities.
  •  Anencephaly—an underdeveloped brain and an incomplete skull. A baby born with anencephaly might be stillborn or survive only a few hours to days after birth.
The quad screen has been shown to identify:
  • 90%-100% of babies with open spines or brains
  • 75% of babies with openings in the abdomen
  •  81% of babies with Down Syndrome
However, any type of testing can result in “false positives” and “false negatives,” therefore missing some babies that do have genetic abnormality.
MaterniT21 panel
If the quad screen results in a positive, the provider may then order a Materni T21 panel (also known as the MaterniT21 PLUS test).
The MaterniT21 is a laboratory-developed test that analyzes circulating cell-free DNA extracted from a maternal blood sample. This test detects the relative amount of 21, 18, 13, and Y chromosomal material.
This testing is a much more in-depth test analysis of the DNA chromosome(s) specifically targeted toward Trisomy 21, 18, and 13. This test is more commonly used in patients with:
  • Advanced maternal age (over age 35)
  • Personal/family history of chromosomal abnormalities
  • A fetal ultrasound abnormality prior to testing
  • A positive serum screening test (such as with the quad screen)
Coding for genetic tests
The laboratory itself generally performs the CPT coding for specific genetic tests. The coding can involve many complex tests and test combinations for genetic testing and screening. Most coders in the physician office will only be coding for the screening of these tests and should use the appropriate diagnosis codes such as:
  • V26.31, Testing of female for genetic disease carrier status
  • V26.32, Other genetic testing of female
  •  V26.34, Testing of male for genetic disease carrier status
  • V26.35, Encounter for testing of male partner of female with recurrent pregnancy loss
  • V26.39, Other genetic testing of male
  • V28.89, Other specified antental screening
  • V82.71, Screening for genetic disease carrier status
  • V82.79, Other genetic screening
The above list is not an all inclusive list of diagnoses for antenatal genetic testing and screening. The medical necessity and documentation will guide you as to what diagnosis should be reported.
If you are coding the CPT codes for the genetic tests, then review and follow the strict guidelines set forth by CPT for accurate coding and billing for these genetic testing procedures.
Editor’s note: Lori-Lynne A. Webb, CPC, CCS-P, CCP, CHDA COBGC, is an independent coding consultant located in Melba, Idaho. She  is also an AHIMA ICD-10-CM/PCS-accredited trainer and an AHIMA ACE Mentor. You can reach her at 208-965-0230 or at
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