Description:
Two of the prenatal genetic and chromosomal metabolic tests are amniocentesis and chorionic villus sampling.

Amniocentesis involves the withdrawal of amniotic fluid for use in diagnosing and assessing various prenatal states. Under local anesthesia and ultrasound guidance, a needle is inserted into the amniotic sac, and amniotic fluid is withdrawn.

Biochemical and serologic analysis of the fluid is performed, and cytogenetic determinations may be performed on cultured fetal cells obtained from the amniotic fluid. The fluid removed is then used to diagnose fetal genetic abnormalities, assess fetal lung maturity and establish the severity of hemolytic disease in blood group isoimmunization. The results can guide in the timing of cesarean section, fetal transfusion or counseling related to the diagnosis of genetic disorders.

Chorionic villus sampling (CVS) is a prenatal genetic testing procedure that may be performed in the later part of the first trimester of pregnancy.

CVS is performed by obtaining samples of villi, which are minute, finger-like projections on the fetal membrane surface of the chorionic tissue attached to the placenta.

Sampling involves a number of methods, including the transcervical (TC) route or the transabdominal (TA) route, with both methods requiring ultrasonic guidance by passing a catheter within the chorion frondosum site. Samples are drawn by aspirating tissue into a syringe attached distally to the catheter (TC route) or a needle (TA route).

CVS permits the diagnosis of genetic disease in the fetus as early as the eighth week of gestation, compared to amniocentesis, which is performed following the 16th week.

Policy:
Amniocentesis and CVS are not medically necessary for all pregnancies. They are MEDICALLY NECESSARY for the specific indications listed under the Policy Guidelines.

Policy Guidelines:
Amniocentesis and CVS are MEDICALLY NECESSARY when any one of the following conditions exist as specified:

1. In pregnancies where the woman will be 35 years of age or over at the expected time of delivery
2. When a previous pregnancy has resulted in the birth of a child with chromosomal (e.g., Down syndrome) or genetic abnormality or major malformations
3. When a chromosomal or genetic abnormality is known to exist in either parent
4. When a history of chromosomal or genetic abnormality is present in a blood relative
5. When there is a history of multiple (three or more) spontaneous abortions in this marriage or in a previous mating of either spouse
6. When the fetus is at an increased risk for a hereditary error of metabolism detectable in vitro
7. Only for amniocentesis, in pregnancies with Rh incompatibility sensitization
8. Only for amniocentesis, when there is a question regarding fetal lung maturity
9. Only for amniocentesis, when the fetus is at an increased risk for a neural tube defect (e.g., family history or elevated maternal serum alpha-fetoprotein level)

A relatively infrequent indication for amniocentesis and CVS is for fetal sex determination in pregnancies at risk for an X-linked hereditary disorder. Such conditions would include the following:

• Hemophilia
• X-linked mental retardation
• X-linked hydrocephalus
• Duchenne muscular dystrophy

In these conditions, only the male child manifests the genetic abnormality and inherits the trait from the mother, who is a carrier but usually free of overt symptoms. Amniocentesis and CVS are NOT MEDICALLY NECESSARY when performed purely for sex determination in the absence of a documented increased risk of an X-linked disorder.

Benefit Application
Reimbursement for amniocentesis should include any required supervision and interpretation of an ultrasonic guidance or the supervision, interpretation or performance of sonography (ultrasound) as part of the procedure. No separate reimbursement should be provided.

Both should be covered as a diagnostic surgical procedure or under maternity benefits, depending on contract or certificate of coverage language.

Payment should not be made for both CVS and amniocentesis on the same patient during a pregnancy unless specific medical justification for doing both tests is provided, which may include confirmation of chromosomal abnormalities detected with CVS.

The use of these tests as a routine screening for all pregnant women is NOT MEDICALLY NECESSARY and should not be covered.

When these procedures are performed on an inpatient basis, some justifiable underlying condition of sufficient severity that warranted hospitalization must have been present.

Reimbursement for the office or outpatient visit should be part of the procedure if the visit is for CVS. The ultrasound examination and ultrasonic guidance are included with the chorionic villus sampling.

References:

1. Staessen C, Platteau P, Van Assche E, et al. Comparison of blastocyst transfer with or without preimplantation genetic diagnosis for aneuploidy screening in couples with advanced maternal age: A prospective randomized controlled trial. Hum Reprod. 2004;19(12):2849-2858.
2. Twisk M, Mastenbroek S, van Wely M, et al. Preimplantation genetic screening for abnormal number of chromosomes (aneuploidies) in in vitro fertilisation or intracytoplasmic sperm injection. Cochrane Database Syst Rev. 2006;(1):CD005291.
3. Sierra S, Stephenson M. Genetics of recurrent pregnancy loss. Semin Reprod Med. 2006;24(1):17-24. 

Coding Section 

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy. They may not be all-inclusive. 

Policy to remain active, but will not undergo scheduled review after 2015.

Index 
Amniocentesis
Chorionic Villus Sampling
Prenatal Diagnosis, Chorionic Villus Sampling, Amniocenteses
Prenatal Genetic and Chromosomal Metabolic Testing

This medical policy was developed through consideration of peer-reviewed medical literature generally recognized by the relevant medical community, U.S. FDA approval status, nationally accepted standards of medical practice and accepted standards of medical practice in this community, Blue Cross Blue Shield Association technology assessment program (TEC) and other non-affiliated technology evaluation centers, reference to federal regulations, other plan medical policies and accredited national guidelines. 

"Current Procedural Terminology^© American Medical Association. All Rights Reserved"  

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