Test Directory
Factor IX (9) Duplication/Deletion Analysis by MLPA                                                
                                            
                                            Justification
                       Hemophilia B is due to mutations in the Factor IX (9) gene. Knowing the mutation can inform likelihood of inhibitor development, bleeding severity, family planning, and pregnancy and neonatal management. Over 10% of severe hemophilia B cases are due to large deletion or duplication variants which are very difficult to detect via sequencing.                      
                    
                    
                    Specimen Requirements
| Sample Type | Volume Required | Minimum Volume | Stability | |
|---|---|---|---|---|
| PREFERRED | EDTA Whole Blood | 3mL | 1mL | Room Temp.: 1 month Refrigerated: 1 month | 
| ALTERNATIVE | Cheek swab | 2 swab | - | Room Temp.: 1 month Refrigerated: 1 month | 
| REJECTION CRITERIA | Sample contamination; sample compromised | 
| SPECIAL INSTRUCTIONS | - | 
General Information
| METHODOLOGY | MLPA | 
| STAT TAT | < 48 hours (M-F) | 
| STAT TAT Performance | > 90% of results released in 48 hours | 
| ROUTINE TAT | < 5 days (M-F) | 
| ALTERNATIVE NAMES | Hemophilia B, FIX (9) copy number variant (CNV) analysis | 
| DESCRIPTION | This test looks for deletions or duplications within the F9 gene by multiplex ligation-dependent probe amplification (MLPA), a method with much higher resolution than next-generation sequencing or microarrays. | 
| LIMITATIONS | This test detects deletions and duplications but not balanced structural variants (i.e., inversions, insertions or translocations). This test requires two consecutive probes indicating a deletion or duplication to make a CNV call. | 
| NORMAL RANGE | Interpretation: Negative | 
| ASSOCIATED TESTING | - | 
| REFERENCES | Johnsen JM, et al. Novel approach to genetic analysis and results in 3000 hemophilia patients enrolled in the My Life, Our Future initiative. Blood Adv. 2017 May 18;1(13):824-834. | 
| SAMPLE REPORT | Upon request | 
| NEW YORK STATE APPROVED | No | 
Test Codes
| ORDER CODE | P3399 | 
| CPT CODE | 81479 | 
| LOINC CODE | 93811-8 |