Hereditary Diffuse Gastric Cancer

CPT codes: 81403 (site specific analysis)

Methodology: Site specific testing using DNA sequencing for known familial mutations in the E-cadherin gene, CDH1.

Indication: This test is used for predictive and diagnostic testing for hereditary diffuse gastric cancer (HDGC) in individuals who have a family member with a known CDH1 gene mutation. This test is used for confirming a CDH1 gene mutation identified on a research basis.

Required paperwork: DNA Diagnostic Laboratory Test Request Form. For site-specific testing, a copy of a laboratory report documenting the familial mutation is beneficial, but not required.

Availability: Weekly

Maximum turnaround time: 14 days

Price: Available upon request by calling (313) 870-1700

Specimen: Blood

Volume: 10-15 ml

Minimum volume: Smaller volumes will be accepted by prior arrangement with the DNA Diagnostic Laboratory. In these cases, 3 ml or less may be sufficient.

Container: Lavender top (EDTA) Vacutainer tubes.

Collection: The blood should be collected by venipuncture in EDTA (lavender top) Vacutainer tubes. Invert several times to mix with anticoagulant. If the blood is collected in a syringe, it should be transferred to the tube by removing the Vacutainer cap and expelling the contents of the syringe without using a needle. The cap should be replaced on the tube and the tube should be vented by piercing the cap with a needle.

Storage instructions: Samples should be drawn as early in the day as possible so they can be delivered to the laboratory the same day. If a specimen is obtained too late in the day to be delivered, it should be stored at room temperature and sent the next day. Blood should be maintained and shipped at room temperature. DO NOT HEAT OR FREEZE THE BLOOD SAMPLE.

Causes for rejection: Clotted, hemolyzed, or frozen specimen; specimen more than 72 hours old; improper anticoagulant; specimen without DNA Diagnostic Laboratory Request Form; improper indication; improper labeling; or evidence of possible co-mingling of specimens.

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