For fetal testing when both parents are known carriers of one of the variants detected by Cystic Fibrosis (CFTR) 165 Pathogenic Variants (2013661) OR fetus has an echogenic bowel.
- Patient Preparation
- Fetal Specimen: Two T-25 flasks of cultured amniocytes at 80 percent confluency. *If the client is unable to culture amniocytes, this can be arranged by contacting ARUP Client Services at (800) 522-2787.
Maternal Specimen: Lavender (EDTA), Pink (K2EDTA), or Yellow (ACD Solution).
- Specimen Preparation
- Cultured Amniocytes: Fill flasks with culture media. Backup cultures must be retained at the client's institution until testing is complete.
Maternal Specimen: Transport 3 mL whole blood. (Min. 1 mL)
- Storage/Transport Temperature
- CultureAmniocytes: CRITICAL ROOM TEMPERATURE. Must be received within 48 hours of shipment due to lability of cells.
- Unacceptable Conditions
- Maternal Specimen: Plasma or serum. Specimens collected in sodium heparin or lithium heparin tubes.
- Maternal sample is recommended for proper test interpretation; order Maternal Cell Contamination, Maternal Specimen. Patient History Form is available on the ARUP Web site or by contacting ARUP Client Services.
- Fetal Specimen: Ambient: 48 hours; Refrigerated: Unacceptable; Frozen: Unacceptable
Maternal Specimen: Ambient: 72 hours; Refrigerated: 2 weeks; Frozen: 1 month
Characteristics of Classic Cystic Fibrosis (CF): Chronic sino-pulmonary disease, gastrointestinal malabsorption/pancreatic insufficiency, and obstructive azoospermia. Symptoms of a CFTR- related disorder are often limited to a single organ system such as isolated pancreatitis, bilateral absence of the vas deferens, nasal polyposis, or bronchiectasis.
Incidence: 1 in 2,300 Ashkenazi Jewish, 1 in 2,500 Caucasians, 1 in 13,500 Hispanics, 1 in 15,100 African Americans, 1 in 35,100 Asians.
Inheritance: Autosomal recessive.
Penetrance: High for severe and moderately severe pathogenic variants, variable for mild pathogenic variants.
Cause of Classic CF: Two severe, or one severe and one moderate, pathogenic CFTR variants on opposite chromosomes.
Cause of CFTR-Related Disorders: Two pathogenic CFTR variants on opposite chromosomes in any of the following combinations; two mild, one mild and one severe or one mild and one moderate.
Pathogenic Variants Tested: Refer to Additional Technical Information document.
Clinical Sensitivity: Ashkenazi Jewish 96 percent; Caucasian 92 percent; Hispanic 80 percent; African American 78 percent; Asian American 55 percent.
Methodology: Polymerase chain reaction (PCR) and fluorescence monitoring.
Analytical Sensitivity & Specificity: 99 percent.
Limitations: Diagnostic errors can occur due to rare sequence variations. Only the 165 pathogenic CFTR variants and 5T variant will be interrogated.
For quality assurance purposes, ARUP Laboratories will confirm the above result at no charge following delivery. Order Confirmation of Fetal Testing and include a copy of the original fetal report (or the mother's name and date of birth) with the test submission. Please contact an ARUP genetic counselor at (800) 242-2787 extension 2141 prior to specimen submission.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|0050548||Maternal Contamination Study Fetal Spec||59266-7|
|0050612||Maternal Contam Study, Maternal Spec||31208-2|
|2013675||Cystic Fibrosis, Allele 1||42938-1|
|2013676||Cystic Fibrosis, Allele 2||42939-9|
|2013680||Cystic Fibrosis, 165 Var Fetal, Interp||38404-0|
|2013692||Cystic Fibrosis 5T Variant||21654-9|
- Fetal CF screening test