First-Trimester Detection of Down Syndrome Using Fetal Ultrasound Markers Combined with Maternal Serum Assessment

POLICY NUMBER

L.4.01.404

DESCRIPTION

Ultrasound markers can potentially increase the sensitivity of biochemical measures for first trimester detection of Down syndrome. Nuchal translucency (NT) refers to the ultrasound detection of subcutaneous edema in the fetal neck between weeks 10 and 13 of gestation. Fetal nasal bone examination involves ultrasound assessment at 11-14 weeks’ gestation to identify the presence or absence of the nasal bone.

Definitive diagnosis of Down syndrome and other chromosomal abnormalities requires amniocentesis or chorionic villus sampling (CVS), both of which are invasive procedures that carry a risk of miscarriage estimated at 0.5% to 1%. Because of this risk, before biochemical screening existed, diagnosis was generally only offered to women 35 years or older, for whom the risk of the procedure approximated the risk of Down syndrome. However, the majority of babies with Down syndrome are born from mothers younger than 35 years, even though the mothers are at lower individual risk. This situation created interest in developing less-invasive screening programs based on assessment of serum markers that have shown associations with Down syndrome. In the late 1980s, biochemical screening at 16 weeks' gestation was developed and began to be offered to all pregnant women. Biochemical screening consists of maternal serum measurements of alpha-fetoprotein, human chorionic gonadotropin, and unconjugated estriol (i.e., triple screen). More recently, there has been the option of a fourth marker, inhibin-A (quadruple screen). The triple screen identifies approximately 69% of Down syndrome pregnancies and the quadruple screen 81%, both at a 5% false-positive rate. This false-positive rate refers to the proportion of all tests administered that are falsely positive at the cutoff point that produces that particular value of sensitivity. Among women who test positive, only about 2% actually have a fetus with Down syndrome.

There has also been interest in ultrasound markers to improve the accuracy of biochemical screening. One potential marker is fetal nuchal translucency. This refers to the ultrasound detection of subcutaneous edema in the fetal neck, and is measured as the maximal thickness of the sonolucent zone between the inner aspect of the fetal skin and the outer aspect of the soft tissue overlying the cervical spine or the occipital bone. In the early 1990s, screening studies of pregnant women reported an association between increased nuchal translucency in the first trimester of pregnancy (10–13 weeks of gestation) and chromosomal defects, most commonly Down syndrome (trisomy 21), but also trisomy 18 and 13. Nuchal translucency could be done alone as a first-trimester screen, or in combination with the maternal serum markers free beta subunit of human chorionic gonadotropin (B-hCG) and pregnancy-associated plasma protein-A (PAPP-A). These are different serum markers than those used in the second-trimester triple or quadruple screen.

Another potential ultrasound marker is fetal nasal bone examination. The technique for assessing the nasal bone using ultrasound involves viewing the fetal face longitudinally and exactly in the midline. The nasal bone synostosis resembles a thin echogenic line within the bridge of the nose. The nasal bones are considered to be present if this line is more echogenic than the overlying skin and absent if the echogenicity is the same or less than the skin, or if it is not visible. The absence of fetal nasal bone is considered to be a positive test result, indicating an increased risk of Down syndrome. In some cases, the sonographer will not be able to visualize the nasal area of the fetus’s face and thus cannot make a determination of the presence or absence of nasal bone. The inability to visualize the nasal bone is regarded as an unsuccessful examination, rather than a positive test result. Fetal nasal bone examination can be done from 11 weeks to just before 14 weeks of gestation. It is sometimes recommended that, if the nasal bone is absent on ultrasound done between 11 and 12 weeks of gestation, a second examination be done two weeks later. Fetal nasal bone assessment can be done along with nuchal translucency, or in the second step of a two-stage screen for cases that are borderline using other first-trimester markers.

Note: This policy only addresses the ultrasound markers nuchal translucency and fetal nasal bone assessment.

Fetal ultrasound uses available instrumentation and as a medical procedure is not subject to regulation by the U.S. Food and Drug Administration.

POLICY

First-trimester screening for detection of Down syndrome incorporating maternal serum markers and measurement of fetal nuchal translucency may be considered medically necessary for women who are adequately counseled and desire information on the risk of having a child with Down syndrome.

First-trimester screening for detection of Down syndrome using measurement of nuchal translucency alone is investigational. 

First-trimester screening for detection of Down syndrome incorporating fetal nasal bone assessment translucency is investigational.

POLICY EXCEPTIONS

None

POLICY GUIDELINES

The coverage guidelines outlined in the Medical Policy Manual should not be used in lieu of the Member's specific benefit plan language.

Medically Necessary is defined as those services, treatments, procedures, equipment, drugs, devices, items or supplies furnished by a covered Provider that are required to identify or treat a Member's illness, injury or Mental Health Disorders, and which Company determines are covered under this Benefit Plan based on the criteria as follows in A through D:

A.  consistent with the symptoms or diagnosis and treatment of the Member's condition, illness, or injury; and

B.  appropriate with regard to standards of good medical practice; and

C.  not solely for the convenience of the Member, his or her Provider; and

D.  the most appropriate supply or level of care which can safely be provided to Member. When applied to the care of an Inpatient, it further means that services for the Member's medical symptoms or conditions require that the services cannot be safely provided to the Member as an Outpatient.

For the definition of medical necessity, “standards of good medical practice” means standards that are based on credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, and physician specialty society recommendations, and the views of medical practitioners practicing in relevant clinical areas and any other relevant factors. BCBSMS makes no payment for services, treatments, procedures, equipment, drugs, devices, items or supplies which are not documented to be Medically Necessary. The fact that a Physician or other Provider has prescribed, ordered, recommended, or approved a service or supply does not in itself, make it Medically Necessary.

Investigative is defined as the use of any treatment procedure, facility, equipment, drug, device, or supply not yet recognized as a generally accepted standard of good medical practice for the treatment of the condition being treated and; therefore, is not considered medically necessary. For the definition of Investigative, “generally accepted standards of medical practice” means standards that are based on credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, and physician specialty society recommendations, and the views of medical practitioners practicing in relevant clinical areas and any other relevant factors. In order for equipment, devices, drugs or supplies [i.e, technologies], to be considered not investigative, the technology must have final approval from the appropriate governmental bodies, and scientific evidence must permit conclusions concerning the effect of the technology on health outcomes, and the technology must improve the net health outcome, and the technology must be as beneficial as any established alternative and the improvement must be attainable outside the testing/investigational setting.

POLICY HISTORY

7/2003: Approved by Medical Policy Advisory Committee (MPAC).

7/15/2005: Reviewed by MPAC, status changed from investigational to covered during first-trimester when ultrasonic measurement of fetal nuchal translucency is used in conjunction with maternal age and other specified tests to detect Down syndrome. First-trimester screening for detection of Down syndrome using measurement of nuchal translucency alone is investigational.

10/17/2005: Code Reference table reviewed; table changed from non-covered to covered. Description of code 76999 revised.

1/29/2007: Code Reference section reviewed. CPT code 76999 and ICD-9 code 758.0 deleted. ICD-9 codes V23.81, V23.82, V26.31-V26.33, and V28.3 added. CPT codes 76813, 76814, 84163, and 84702 added. HCPCS code S3618 added with effective date 4-1-2007

3/29/2007: Policy reviewed, description updated, no change to policy statement.

12/17/2007: Coding updated. CPT/HCPCS 2008 revision added to policy.

5/1/2008: Policy reviewed, no changes.

9/22/2008: Annual ICD-9 updates effective 10-1-2008 applied.

08/03/2010: Policy title changed from “First-Trimester Detection of Down Syndrome Using Fetal Ultrasound Assessment of Nuchal Translucency Combined with Maternal Serum Assessment” to “First-Trimester Detection of Down Syndrome Using Fetal Ultrasound Markers Combined with Maternal Serum Assessment.” Policy description rewritten based on new research findings. The scope of the policy was expanded to include fetal nasal bone assessment. Investigational policy statement added regarding fetal nasal bone assessment.

06/13/2011: Policy review; no changes.

04/26/2012: Policy review; no changes.

12/21/2012:  Added the following new 2013 CPT codes to the Code Reference section: 81508, 81509, 81510, 81511, and 81512.

08/07/2013: Policy reviewed; no changes.

06/12/2014: Policy reviewed; description updated. Policy statement unchanged.

08/26/2015: Medical policy revised to add ICD-10 codes.

09/14/2015: Policy description updated regarding FDA regulation for fetal ultrasound use. Policy statements unchanged. Policy Guidelines section updated to add medically necessary and investigative definitions.

05/27/2016: Policy number A.4.01.14 added.

09/29/2017: Code Reference section updated to add new ICD-10 diagnosis codes Z36.0, Z36.1, and Z36.82. Revised code description for ICD-10 diagnosis code Z31.5. Effective 10/01/2017.

09/17/2019: Code Reference section updated to add new CPT codes 0124U, 0125U, and 0126U, effective 10/01/2019. Removed deleted ICD-10 diagnosis code Z36.

06/25/2020: Code Reference section updated to make note of deleted CPT codes.

03/27/2023: Policy reviewed. Policy statements unchanged. Policy revised to change the medical policy number from "A.4.01.14" to "L.4.01.404." Policy Guidelines updated to change "Nervous/Mental Conditions" to "Mental Health Disorders" and "Medically Necessary" to "medical necessity." Code Reference section updated to remove deleted CPT codes 0124U, 0125U, and 0126U.

04/29/2024: Policy reviewed; no changes.

04/15/2025: Policy reviewed. Policy statements unchanged. Code Reference section updated to add ICD-10 diagnosis codes O09.891, O09.91, O30.91, Z34.01, Z34.81, and Z34.91.

SOURCE(S)

Blue Cross Blue shield Association policy # 4.01.14

CODE REFERENCE

This may not be a comprehensive list of procedure codes applicable to this policy.

The code(s) listed below are ONLY medically necessary if the procedure is performed according to the "Policy" section of this document.

Covered Codes

CPT copyright American Medical Association. All rights reserved. CPT is a registered trademark of the American Medical Association.