Cystic Fibrosis (CFTR) 165 Pathogenic Variants, Fetal
Ordering Recommendation

For fetal testing when both parents are known carriers of one of the variants on the CF 165 variants test OR fetus has an echogenic bowel.

Polymerase Chain Reaction/Fluorescence Monitoring
7-10 days
New York DOH Approval Status
This test is New York DOH approved.
ARUP Consult®
Disease Topics
Specimen Required
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 
Reference Interval
By report
Interpretive Data
Background information for Cystic Fibrosis (CFTR), 165 Pathogenic Variants, Fetal
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.
: 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.
: Autosomal recessive.
: 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.
: Polymerase chain reaction (PCR) and fluorescence monitoring.
Analytical Sensitivity & Specificity
: 99 percent.
: 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.

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.

The CF 165-Variants assay includes the 23 pathogenic CF variants recommended by the American College of Medical Genetics for population carrier screening.
Hotline History
View Hotline History
CPT Code(s)
81220; 81265 Fetal Cell Contamination (FCC)
Component Test Code*Component Chart NameLOINC
0050548Maternal Contamination Study Fetal Spec59266-7
0050612Maternal Contam Study, Maternal Spec31208-2
2013675Cystic Fibrosis, Allele 142938-1
2013676Cystic Fibrosis, Allele 242939-9
2013680Cystic Fibrosis, 165 Var Fetal, Interp38404-0
2013692Cystic Fibrosis 5T Variant21654-9
* 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.
  • Fetal CF screening test