Sickle Cell Anemia Mutation Analysis (Fetal)

CPT 81361
Synonyms Sickle Cell Anemia, Prenatal

Test Details

Turnaround Time

8 - 14 days Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.

Use

DNA analysis to detect mutations known to cause sickle cell anemia

Special Instructions

This test is for fetal/prenatal cases and parental controls. It is not intended for routine sickle cell screening. Please call 800-345-4363 with any questions regarding selection of tests. Prenatal testing: Integrated Genetics clients should call 800-848-4436 to speak to a laboratory genetic coordinator before collecting any specimens. In some circumstances, specimens from other family members may be required. All prenatal specimens (including cord blood) must be accompanied by a maternal blood or mouthwash specimen for analysis of possible maternal cell contamination. Discard first 2 mL; then 10 mL amniotic fluid in 15 mL orange-top polypropylene tube, 10-15 mg chorionic villi in laboratory-provided screw-top tubes with sterile transport medium or one T-25 flask of confluent cells. Additional sample must be obtained for back-up culture at one of our cytogenetics laboratories or another facility. If additional testing is desired, more amniotic fluid is needed. For example, chromosome analysis requires an additional 15-25 mL (see Cytogenetics – Amniotic Fluid Chromosome Analysis test page) and AFAFP requires an additional 2 mL (see Amniotic Fluid Alpha-Fetoprotein - AFAFP test page).

Limitations

False-positive and false-negative results may occur for reasons that include genetic variants, blood transfusions, bone marrow transplantation, erroneous representation of family relationships, or contamination of a fetal sample with maternal cells.

Methodology

A targeted region of the HBB gene is amplified by the polymerase chain reaction (PCR). HbS or HbC mutations are identified by targeted, direct DNA sequencing.

Specimen Requirements

Information on collection, storage, and volume

Specimen

Amniotic fluid, chorionic villi

Volume

Parental samples: 10 mL whole blood / Prenatal: 10 mL amniotic fluid in orange-top polypropylene tube, 10-15 mg chorionic villi in laboratory provided screw-top tubes with sterile transport medium or one T-25 flask of confluent cells.

Container

Lavender-top (EDTA) tube or yellow-top (ACD-A) tube

Storage Instructions

Maintain specimen at room temperature.

Causes for Rejection

Frozen specimen; hemolysis; quantity not sufficient for analysis; improper container; unlabeled or mislabeled specimen