Maternal Cell Contamination, Fetal

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)

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.

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].

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.

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].

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.