Laboratory Test Guide

Maternal Cell Contamination, Fetal

General Information

Lab Name

Lab Code

MCC

Epic Name

Maternal Cell Contamination, Fetal

Description

The contamination of fetal samples with maternal cells can interfere in diagnostic prenatal testing, although the presence of maternal cells does not always cause diagnostic prenatal test errors.

The frequency of contamination varies considerably, due to differences in sampling protocol and the success of fetal cell culture. The degree of maternal cell contamination that affects a prenatal diagnostic test result varies by genetic test and is highly dependent on the technology used by the performing laboratory.

This test evaluates more than 80 polymorphic variants at 10 loci to detect the presence of maternal cells and estimate the percent contamination.

Note that Maternal Cell Contamination Comparator [MCCOMP] must also be ordered in order to perform contamination studies.

Indications for testing include:

As an adjunct to prenatal diagnostic testing (amniocentesis or chorionic villus sampling)

References

Schrijver I, Cherny SC, and Zehnder JL. Testing for maternal cell contamination in prenatal samples: a comprehensive survey of current diagnostic practices in 35 molecular diagnostic laboratories. J Mol Diagn 2007, 9:394-400. 17591939
Steinberg S, Katsanis S, Moser A, and Cutting G. Biochemical analysis of cultured chorionic villi for the prenatal diagnosis of peroxisomal disorders: biochemical thresholds and molecular sensitivity for maternal cell contamination detection. J Med Genet 2005, 42:38-44. 15635073

Synonyms

amniocyte contamination, chorionic villus contamination, DNA fingerprinting, Maternal cell contamination of fetal tissue, MCC studies, prenatal testing

Components

Code	Name
MCCRES	MCC Result
MCCCI	MCC Clinical Information
MCCINT	MCC Interpretation
MCCMTH	MCC Method
MCCDI	MCC Director

Interpretation

Method

Next generation sequencing.

More than 80 polymorphic variants at 10 loci are evaluated. The fetal and maternal alleles are compared and the percent contamination estimated from the variant fractions.

This test was developed and its performance characteristics determined by the Department of Laboratory Medicine and Pathology at the University of Washington.

Reference Range

See individual components

Ref. Range Notes

This test can normally detect contamination when maternal cells exceed about 5% to 20% of the total cells present. The level of maternal cell contamination that could adversely affect the result of a prenatal test varies among different genetic tests, as it is highly dependent upon the technology employed by the testing laboratory.

Guidelines

Genetics and Solid Tumor Diagnostic Testing

Ordering & Collection

Specimen Type

Fetal tissue: amniocytes, chorionic villus, or purified DNA.

Collection

Fetal amniocytes or cultured chorionic villus cells: Two (2) T23 flasks or one (1) T75 flask. The minimum is one (1) T25 flask.

Chorionic villi and/or tissue: Minimum of 5 mg tissue in a sterile tube or culture medium.

Purified DNA: Minimum of 1 ug.

Note: In some cases, the reference lab that performs the prenatal testing does not perform maternal cell contamination testing. That reference lab must then send us a minimum of 1 ug of purified DNA from the fetus. This DNA must be from the same sample that the reference lab will use for its prenatal test. Contact genelab@uw.edu if you have questions.

For the maternal sample, see Maternal Cell Contamination Comparator [MCCOMP].

Forms & Requisitions

Due to the complexity of prenatal testing, consultation with the laboratory is required.

Please contact the Genetics lab by e-mail (genelab@uw.edu) or phone (206-598-1149).

Outside providers: Genetics Requisition.

UW, HMC, and FHCC providers: Place order in Epic.

Handling Instructions

Fetal amniocytes & cultured chorionic villus cells: Hold flasks at room temperature.

Chorionic villi &/or tissue: Hold at room temperature.

Purified DNA: Refrigate the entire tube (up to 4 weeks).

Outside Laboratories:
For cultured amniocytes, chorionic villi, and other tissue, store at room temperature within 24 hours of obtaining CV or removing cultured cells from incubator. Transport at room temperature.

For purified DNA, ship on a cold pack.

For the maternal sample, see Maternal Cell Contamination Comparator [MCCOMP].

Quantity

requested: Entire specimen.
minimum: See "Collection," above.

Processing

Log as MCC.

Processing: Please notify the Genetics Lab if you receive amniocytes, cultured chorionic villus cells, chorionic villi, or tissue.

Note: This test (MCC) is paired with MCCOMP. MCC and MCCOMP will typically arrive at different times.

Performance

LIS Dept Code

Genetics (GEN)

Performing Location(s)

UW-MT	Genetics Attention: Genetics Lab Clinical lab, Room NW220 University of Washington Medical Center 1959 NE Pacific Street Seattle, WA 98195 Tel: 206-598–6429 M–F (7:30 AM–4:00 PM) Fax: 206-616-4584 Lab email: cgateam@uw.edu Tel (EXOME only): 206-543-0459	Faculty Jillian Buchan, PhD, FACMG Runjun Kumar, MD, PhD Regina Kwon, MD, MPH Christina Lockwood, PhD, DABCC, DABMGG Abbye McEwen, MD, PhD Colin Pritchard, MD, PhD Vera Paulson, MD, PhD Eric Konnick, MD, MS He Fang, PhD

Frequency

Performed as submitted.

Available STAT?

No.

Billing & Coding

CPT codes

81479

Billing Comments

For pricing information, contact Client Support Services at 206-520-4600 or 800-713-5198.

LOINC

59266-7

Interfaced Order Code

UOW1408