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Test ID: NIPS Cell-Free DNA Prenatal Screen

Useful For

Noninvasive screening for aneuploidies of chromosomes 13, 18, and 21 in pregnancies

Testing Algorithm

This test is only available to clients in North and South America.

 

When this test is ordered, additional statistical analysis to determine the percentage of fetal DNA present is always performed.

 

The following algorithms are available in Special Instructions:

-Prenatal Aneuploidy Screening and Diagnostic Testing Options

-High-Risk Pregnancy Based on Abnormal Fetal Malformations: Laboratory Testing Algorithm

Method Name

Whole Genome Sequencing of Plasma Cell-Free DNA

Reporting Name

Cell-Free DNA Prenatal Screen

Specimen Type

Whole blood


Advisory Information


This screen is available for patients starting at 10-weeks gestation.



Shipping Instructions


Advise Express Mail or equivalent if not on courier service.



Necessary Information


The following information is required with each specimen:

1. Reason for referral

2. Maternal age

3. Number of fetuses

4. Gestation age (weeks and days)

5. Method of determining gestational age

6. Maternal height (inches)

7. Maternal weight (pounds)

 

The laboratory will not reject testing if this information is not provided, but appropriate testing and interpretation may be delayed or compromised.



Specimen Required


Supplies: Streck Black/Tan Top Tube Kit (T715)

Specimen Volume: Two 10-mL Streck Cell-Free DNA blood collection tubes

Additional Information:

1. Specimens received from patients who are considered "low risk" will not be rejected but insurance may not cover testing.

2. Prior Authorization is available for this test. Submit the required form with the specimen.


Specimen Minimum Volume

One 10 mL Streck tube

Specimen Stability Information

Specimen Type Temperature Time
Whole blood Ambient (preferred) 7 days
  Refrigerated  7 days

Clinical Information

This test provides the ability to detect common chromosome abnormalities, specifically aneuploidy including Down syndrome (trisomy 21), Patau syndrome (trisomy 13), and Edward syndrome (trisomy 18), without the risk of pregnancy loss associated with invasive prenatal procedures. Chromosomal aneuploidy is the leading known genetic cause of miscarriage and congenital birth defects.

 

This fetal DNA screen is not a diagnostic test; therefore, abnormal results should be confirmed with invasive prenatal diagnostic testing (such as chorionic villi sampling or amniocentesis) and a genetic consultation is recommended. In addition, a negative result does not ensure an unaffected pregnancy. The false-negative rate for trisomy 21 is less than 1%, for trisomy 18 is 3.6%, and for trisomy 13 is 9.4%.(1) The positive predictive value in low-risk pregnancies is lower than in pregnancies at high risk for aneuploidy.(2)

Reference Values

An interpretive report will be provided.

Interpretation

Normal representation of material from chromosomes 13, 18, and 21 will be reported as normal, indicating a low risk for trisomy 13, trisomy 18, and trisomy 21 in the fetus. Fetal sex will be reported. If Y chromosome material is detected, this is suggestive of a male fetus. If Y chromosome material is not detected, this is suggestive of a female fetus.

 

Increased amounts of chromosomal material will be reported as positive for having a trisomy of the identified chromosome for chromosomes 13, 18, or 21. 

While most specimens undergoing this analysis can be readily characterized, on rare occasions equivocal or incidental results such as aneuploidy of chromosomes other than 13, 18, and 21 as well as other genomic unbalanced rearrangements, may not allow for standard interpretation of this aneuploidy screen. In these situations, a new maternal blood specimen may be requested or a recommendation for other screening measures or diagnostic cytogenetic testing will be made.

Clinical Reference

1. Gil MM, Quezada MS, Revello R, et al: Analysis of cell-free DNA in maternal blood in screening for fetal aneuploidies: updated meta-analysis. Ultrasound Obstet Gynecol 2015;45:249-266

2. ACOG/SMFM Joint Committee Opinion: Noninvasive prenatal testing for fetal aneuploidy. No. 640, Dec 2015

3. Bianchi DW, Parker RL, Wentworth J, et al: DNA sequencing versus standard prenatal aneuploidy screening. N Engl J Med 2014 Feb;370:799-808

4. Devers PL, Cronister A, Ormond KE, et al: Noninvasive prenatal testing/noninvasive prenatal diagnosis: the position of the National Society of Genetic Counselors. J Genet Counsel 2013;22:291-295

5. Gregg AR, Skotko BG, Benkendorf JL, et al: Noninvasive prenatal screening for fetal aneuploidy, 2016 update: a position statement of the American College of Medical Genetics and Genomics. Genet Med 2016

6. Jensen TJ, Zwiefelhofer T, Tim RC, et al: High-throughput massively parallel sequencing for fetal aneuploidy detection from maternal plasma. PLOS ONE 2012 Mar;8:1-8

7. Huang X, Zheng J, Chen M, et al: Noninvasive prenatal testing of trisomies 21 and 18 by massively parallel sequencing of maternal plasma DNA in twin pregnancies. Prenatal Diagnosis 2014;34:335-340

Day(s) and Time(s) Performed

Samples processed Monday through Sunday. Results reported Monday through Friday 8 a.m.-5 p.m.

Analytic Time

7 days

CPT Code Information

81420

LOINC Code Information

Test ID Test Order Name Order LOINC Value
NIPS Cell-Free DNA Prenatal Screen In Process

 

Result ID Test Result Name Result LOINC Value
37873 Result Summary 50397-9
37909 Result 79211-9
37910 Interpretation 69047-9
37874 Reason for Referral 42349-1
37875 Specimen 31208-2
37876 Maternal Height (inches) 3137-7
37877 Maternal Weight (pounds) 3141-9
37878 Gestational Age (weeks) 49051-6
37879 Gestational Age (days) 49052-4
37899 Method Used to Determine Gest Age 21299-3
37900 Number of Fetuses 11878-6
37911 Method 49549-9
37912 Additional Information 48767-8
37913 Disclaimer 62364-5
37914 Released By No LOINC Needed

Forms

1. New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (T576) is available in Special Instructions.

2. Cell-Free DNA Prenatal Screen Prior Authorization Ordering Instructions in Special Instructions.

3. Cell-Free DNA Prenatal Screen Patient Information in Special Instructions.

4. Cell-Free DNA Prenatal Screen Patient Information FAQ in Special Instructions.

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.
Mayo Medical Laboratories | Genetics and Pharmacogenomics Catalog Additional Information:

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