Familial Hyperinsulinism

Test Code

92045

CPT Codes
81401

Physician Attestation of Informed Consent

This germline genetic test requires physician attestation that patient consent has been received if ordering medical facility is located in AK, DE, FL, GA, IA, MA, MN, NV, NJ, NY, OR, SD or VT or test is performed in MA.

Preferred Specimen

5 mL whole blood collected in an EDTA (lavender-top) tube or ACD (yellow-top) tube

Minimum Volume

4 mL whole blood • 2 mL (x2) cultured amniocytes • 10 mL amniotic fluid • 10 mg chorionic villus sampling

Other Acceptable Specimens

Whole blood collected in: Sodium heparin (green-top) tube • Cultured amniocytes • Amniotic fluid • Chorionic villus sampling

Instructions

Whole blood: Specimen stability is crucial. Store and ship room temperature immediately. Do not freeze.
For prenatal diagnosis with a fetal specimen:
1. Parents must be documented carriers of one of the mutations tested.
2. Maternal blood or DNA must be available.
3. Contact the laboratory genetic counselor before submission.

Amniotic fluid: 15 mL. Specimen stability is crucial. Store and ship room temperature immediately. Do not refrigerate or freeze.

Amniocyte culture: 5 mL (X2). Sterile T25 flask, filled with culture medium. Specimen stability is crucial. Store and ship room temperature immediately. Do not refrigerate or freeze.

Dissected chorionic villus (CVS) biopsy: 10-20 mg dissected chorionic villi collected in sterile tube filled with sterile culture medium. Specimen stability is crucial. Store and ship room temperature immediately. Do not refrigerate or freeze.

Forward cells to laboratory immediately..

Transport Temperature

Room temperature

Specimen Stability

Whole blood
Room temperature: 14 days
Refrigerated: 8 days
Frozen: Unacceptable

Cultured amniocytes, Amniotic fluid, CVS
Room temperature: 8 days
Refrigerated: Unacceptable
Frozen: Unacceptable

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Do not accept blood that is clotted • Samples received frozen • Samples shipped in damaged containers • Wrong test indicated

Methodology
PCR amplification of specific gene regions followed by nucleotide sequence analysis on a massively parallel sequencing platform

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule

Report available: 10-15 days

Clinical Significance

The familial hyperinsulinism (FH) test offers molecular detection of two common pathogenic variants in the ABCC8 gene, IVS32-9G>A (c.3989-9G>A) and F1387del (c.4160_4162delTCT), which account for approximately 90% of Ashkenazi-Jewish FH pathogenic variants.

FH is an autosomal recessive disorder characterized by an inability to suppress insulin production that results in hypoglycemia (low blood sugar).

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.