Casandra

Casandra Test Code AR72783Version 1 (DRAFT)

Performing Lab

Lab ARUP LaboratoriesLab Test ID 3000258CPT Codes 81220, 81243, 81244, 81329

Genetic Carrier Screen, (CF, FXS, and SMA) with Reflex to Methylation

Also known as: CF FX SMA

Clinical Use

Use

This genetic carrier screening test is specifically designed for women who are pregnant or planning to become pregnant. It provides carrier status for three genetic conditions: cystic fibrosis (CF), fragile X syndrome (FXS), and spinal muscular atrophy (SMA). The test is important for assessing the reproductive risk for these conditions, enabling informed decision-making and family planning. Although it is not meant for men, as FXS carrier screening is not indicated for them, it gives critical information for preconception and prenatal genetic counseling.

Special Instructions

Not provided.

Limitations

This test might not detect rare FMR1 variants causing less than 1% of FXS cases. Other limitations include potential diagnostic errors due to rare sequence variations, and it does not assess AGG trinucleotide interruptions in the FMR1 CGG repeat. For CF, only specified CFTR variants are tested, and it cannot detect other pathogenic variants outside this range. Similarly, for SMA, the test won't identify single nucleotide variants, small deletions, or intronic variations beyond the tested regions. Results should be interpreted in conjunction with clinical findings and possibly further genetic consultation.

Test Details

New York Approved

Methodology

Mass Spectrometry

Biomarkers

3 components

Fragile X Syndrome Analysis • PCRCystic Fibrosis PanelSMA Copy Number Analysis • Flow Cytometry

LOINC Codes

Result Codes

45321-7 - FMR1 allele1 CGG Rpt EntNum Bld/T
45322-5 - FMR1 allele 2 CGG Rpt EntNum Bld/T
41107-4 - FMR1 gene Mut Anl Bld/T
36913-2 - FMR1 gene Mut Anl Bld/T
66746-9 - Specimen type
31208-2 - Specimen source
75325-1 - Symptom
35462-1 - SMN1 gene Mut Anl Bld/T
54449-4 - SMN2 gene Mut Anl Bld/T
82155-3 - Gen struct var copy num
49857-6 - SMN1+SMN2 gene Mut Anl Bld/T
42938-1 - CFTR allele 1 Bld/T Ql
42939-9 - CFTR allele 2 Bld/T Ql
21656-4 - CFTR Mut Tested Bld/T
21654-9 - CFTR Mut Anl Bld/T

Result Turnaround Time

4-14 days

Specimen

Whole Blood

Volume

5 mL

Minimum Volume

3 mL

Container

Lavender (K2EDTA) or Pink (K2EDTA)

Storage Instructions

Refrigerated

Causes for Rejection

Plasma or serum. Specimens collected in sodium heparin, yellow (ACD solution A), or lithium heparin tubes. Frozen specimens in glass collection tubes.