Maternal Cell Contamination

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General Information

Lab Name
Maternal Cell Contamination
Lab Code
MCC
ORCA Name
Maternal Cell Contamination
Description

The contamination of fetal samples with maternal cells is cause for concern in prenatal testing. The frequency of maternal cell contamination varies considerably due to sampling protocol, operator and culturing of cells from the fetal sample. The presence of maternal cells does not always lead to a prenatal diagnostic error. The level of maternal cell contamination that could adversely affect a prenatal test result varies among different genetic tests, as it is highly dependent upon the technology employed by the testing laboratory. Maternal cell contamination testing detects the presence and estimates the percentage of contamination. At least five polymorphic loci are evaluated. This test result, in conjunction with the prenatal test result, the sensitivity of the prenatal test to maternal cell contamination, and the known genotype of the mother, provides the basis for accurate prenatal diagnosis.

Five polymorphic loci on different human chromosomes are amplified by PCR from the genomes of both the fetus and mother. Fluorescent-labeled amplicons are analyzed by capillary electrophoresis. Alleles of the fetus are compared to those of the mother to determine if the fetal tissue is contaminated with maternal cells.

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
Forms & Requisitions

Genetics Requisition

Synonyms
DNA fingerprinting, Maternal cell contamination of fetal tissue, amniocyte contamination, chorionic villus contamination, mcc studies, prenatal testing
Components

Interpretation

Method

Next generation sequencing.

Over eighty polymorphic varaints at 10 loci are assayed from the fetal and maternal specimens. The fetal and maternal alleles are compared and the percent contamination estimated from variant fractions. This test was developed and its performance characteristics determined by the Department of Laboratory Medicine at the University of Washington.

Reference Range
See individual components
Ref. Range Notes

No contamination detected. 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.

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

Ordering & Collection

Specimen Type
Fetal sample: amniocytes, chorionic villus, or purified DNA; Maternal sample: blood or purified DNA
Collection

Maternal blood: - Adult: 5 mL lavender top tube- Also acceptable: yellow top (ACD) tube - Unacceptable : heparin green top tubes DNA: 3 ug purified DNA (with concentration given) in a screwcap tube

Fetal amniocytes or cultured chorionic villus cells: - (2) T23 or (1) T75 flask (minimum of 1-T25 flask)

Chorionic villi and/or tissue in a sterile tube or culture media: - Minimum 5 mg tissue

Forms & Requisitions

Genetics Requisition

Handling Instructions

Maternal Blood: Refrigerate whole blood up to 1 week.

Fetal amniocytes & cultured CVS cells: hold flasks at room temperature.

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

Outside Laboratories: Ship whole blood at ambient temperature for receipt within 1 week of specimen collection.- For cultured amniocytes or chorionic villus cells and for CVS or other tissue, transport and store at room temperature within 24 hours of obtaining CV or removing cultured cells from incubator. - Ship purified DNA on a cold pack. Refrigerate entire tube up to 4 weeks.

Quantity
requested: Entire specimen
minimum: Blood: 1 mL. Amniocytes, cultured chorionic villus cells, chorionic villi, tissue or purified DNA: as above.

Processing

Processing

Processing: Please notify genetics about amniocytes, cultured chorionic villus cells, chorionic villi or tissue.

Maternal Blood: Log as DNAPRP.

The following sample types, login as MCC.

  • Fetal amniocytes & cultured CVS cells
  • Chorionic villi &/or tissue

Note: Samples from mother and fetus will often arrive at different times. In some cases, prenatal testing for a rare genetic disorder may be performed by a reference lab that does not offer testing for maternal cell contamination. In this instance, the MCC test sample requirement is at least 3 ug of DNA purified from the fetus by the reference lab (i.e., the same DNA they used for the prenatal test).

Performance

LIS Dept Code
Genetics (GEN)
Performing Location(s)
UWMC 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: 206-598–0304
Lab email: genelab@uw.edu

Supervisor

Robert Livingston, PhD bobl@uw.edu

Genetic Counselors

Angela Jacobson, MS, LGC agibson@uw.edu
Ginger Tsai, MS, LGC, gjtsai@uw.edu

Faculty

Colin C. Pritchard, MD, PhD
Brian H. Shirts, MD, PhD
Christina Lockwood, PhD, DABCC
Stephen Salipante, MD, PhD
Eric Konnick, MD, MS
Karen Stephens, PhD, FACMG
Jonathan F. Tait, MD, PhD
Vera Paulson, MD, PhD

Frequency
Performed as submitted.
Available STAT?
No

Billing & Coding

CPT codes
81479
Billing Comments

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

LOINC
59266-7