Ordering Recommendation

Acceptable diagnostic or predictive test for familial adenomatous polyposis. For classic FAP, consider Familial Adenomatous Polyposis Panel: (APC) Sequencing and Deletion/Duplication, (MUTYH) 2 Mutations (2004915).

Mnemonic
APC FGS
Methodology

Polymerase Chain Reaction/Sequencing

Performed

Varies

Reported

14-28 days

New York DOH Approval Status
Specimens from New York clients will be sent out to a New York DOH approved laboratory, if possible.
Specimen Required
Patient Preparation
Collect

Lavender Lavender (K2EDTA), Pink (K2EDTA), or Yellow (ACD Solution A or B).

Specimen Preparation

Transport 3 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions
Remarks
Stability

Ambient: 1 week; Refrigerated: 1 month; Frozen: 6 months

Reference Interval
Interpretive Data

Background Information for Familial Adenomatous Polyposis (APC) Sequencing:
Characteristics of APC-associated Polyposis:

Familial Adenomatous Polyposis (FAP): Development of hundreds to thousands of adenomatous colonic polyps beginning in early adolescence; lifetime risk for cancer is 100 percent. Additional findings may include dental anomalies, polyps of the gastric fundus and duodenum, and congenital hypertrophy of the retinal pigment epithelium (CHRPE).
Attenuated FAP: Fewer colonic adenomatous polyps (average of 30), which are more proximally located and cancer generally occurs at a later age; lifetime risk for cancer is 70 percent.
Gardner syndrome: Multiple colonic adenomatous polyps along with osteomas, desmoid tumors, and soft tissue tumors.
Incidence:
  Less than 1 percent of colorectal cancer cases.
Inheritance:
  Autosomal dominant.
Penetrance:
  Greater than 99 percent in untreated individuals.
Causes:
  Pathogenic APC allelic variations
Clinical Sensitivity:
Approximately 90 percent for classic FAP and less than 30 percent for attenuated FAP.
Methodology:
Bidirectional sequencing of the APC coding region and intron-exon boundaries. 
Analytical Sensitivity and Specificity:
99 percent.
Limitations
: Diagnostic errors can occur due to rare sequence variations. Regulatory region mutations, deep intronic mutations, and large deletion/duplications will not be detected. This assay is not designed to detect somatic variants associated with malignancy. Interpretation of this test result may be impacted if the patient has had an allogeneic stem cell transplantation.

Compliance Statement C: For human genetic inheritable conditions and mutations. This test was developed and its performance characteristics determined by ARUP Laboratories. The U. S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online.

Note
Hotline History
N/A
CPT Codes

81201

Components
Component Test Code* Component Chart Name LOINC
2004864 FAP (APC) Sequencing Specimen 31208-2
2004865 FAP (APC) Sequencing Interpretation 20990-8
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • APC-Associated Polyposis
  • Attenuated FAP
  • Gardner Syndrome
  • Turcot Syndrome
Familial Adenomatous Polyposis (APC) Sequencing