Maternal Sample (Sendout)

Useful For: Ruling out contamination of a fetal specimen by maternal cells.

Description: Contamination of fetal samples by maternal cells can interfere with diagnostic prenatal testing. Maternal cell contamination (MCC) can occur when a fetal specimen comes into contact with maternal blood or tissue, such as during chorionic villus sampling, amniocentesis, or extraction of cord blood.

To rule out the presence of MCC, a maternal blood specimen is required for comparison of maternal and fetal chromosomal markers.

Ordering Note: For use with prenatal sendout testing only. For testing performed by the UW Genetics Lab, refer to separate tests Maternal Cell Contamination, Fetal [MCC] and Maternal Cell Contamination Comparator [MCCOMP].

Maternal blood (or DNA) samples may precede or follow the submission of the fetal sample (amniotic fluid, cultured amniocytes, CVS).

Maternal Blood: 5 mL blood in a lavender top tube.

• Note: Preferred tube type and size may vary. Follow the collection requirements provided by the performing lab.

Maternal DNA: 3 mcg purified DNA in a screw-cap tube (concentration should be indicated on the sample).

SPS: Log RMCSND. Indicate the Specimen Type and Performing Lab in the corresponding result-at-entry fields.

• RMCCS (MCC Sendout Specimen): WB or DNAEXT
• RMCCL (MCC Ref Lab Name): [Performing Lab Code]

Store whole blood at room temperature. Refrigerate extracted DNA.

The associated fetal sample (chorionic villi, cultured amniocytes or cultured cv, etc.) may be submitted concurrently or at a later date. A separate login (GSEND1) must be generated for the fetal sample; refer to OLTG #896 for further details.

Sendouts: Ship whole blood at ambient temperature (usually within one week of collection); ship DNA refrigerated. Sample and stability requirements may vary; consult with the performing lab as needed.

The performing lab may require a separate test order for the maternal sample, or MCC testing may be included in the prenatal panel. If fetal cells are being cultured, indicate to the performing lab that the fetal sample will follow (do not delay shipment of maternal blood or DNA). Select MCC test codes are listed below.

• ARUP Maternal Cell Contamination, Maternal Specimen: 0050608
• Mayo Maternal Cell Contamination, Molecular Analysis: MATCC
• Quest Diagnostics Maternal Cell Contamination Study, STR Analysis: 10262
• LabCorp Maternal Cell Contamination: 511402