Ordering Recommendation

Alternate test when clinical/family history is classic for HHT. Test does not detect large duplications/deletions.

Mnemonic
HHT-FGS
Methodology

Polymerase Chain Reaction/Sequencing

Performed

Varies

Reported

28-35 days

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
Collect

Lavender (EDTA), 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: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable

Reference Interval

By report

Interpretive Data

Background Information for Hereditary Hemorrhagic Telangiectasia (ACVRL1 and ENG) Sequencing
Characteristics:
Recurrent nosebleeds, telangiectases (mouth, face, hands, GI tract), arteriovenous malformations (lung, brain, liver, spine).
Incidence:
1:5,000-10,000
Inheritance:
Autosomal dominant
Penetrance:
Approaches 100 percent by age 40.
Cause:
  Pathogenic variants in the endoglin (ENG), activin A receptor type II-like 1 (ACVRL1 or ALK1), SMAD4 or other unidentified gene(s).
Clinical Sensitivity:
Approximately 75 percent
Methodology:
Bidirectional sequencing of the coding regions and intron-exon boundaries of ENG and ACVRL1, the 5' untranslated region of ENG, and a region of ACVRL1 intron 9 encompassing the CT-rich variant hotspot region.
Analytic Sensitivity and Specificity: 99 percent
Limitations:
Diagnostic errors can occur due to rare sequence variations. Regulatory region and intronic mutations, large deletions/duplications, and mutations in genes other than ENG and ACVRL1 will not be detected.

Compliance Category

Laboratory Developed Test (LDT)

Note
Hotline History
N/A
CPT Codes

81406 (ENG); 81479

Components
Component Test Code* Component Chart Name LOINC
0051575 HHT, Sequencing
2001357 HHT, Sequencing - Specimen
* 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
  • ACVRL1 and ENG sequencing
  • HHT sequencing
Hereditary Hemorrhagic Telangiectasia (ACVRL1 and ENG) Sequencing (INACTIVE as of 02/16/21)