New Test
Effective Date
02/10/2026
Included in Report
Updated Test
New Test
Test Details
Mnemonic
ELF
Ordering Code
3401121
CPT-4 Codes(s)
81517
Turnaround Time
4 - 5 days
Performed
Tuesday, Thursday, Saturday
Legacy Code
ELF
Example Report
Specimen Information
Patient Preparation
Dietary supplements containing biotin may interfere in assays and may skew analyte results to be either falsely high or falsely low. For patients receiving the recommended daily doses of biotin, draw samples at least 8 hours following the last biotin supplementation. For patients on mega-doses of biotin supplements, draw samples at least 72 hours following the last biotin supplementation.
Collect
Serum separator tube (SST)
Specimen Preparation
Centrifuge, separate serum from cells ASAP or within 2 hours of collection and send 1.0 mL serum in a screw capped plastic vial.
Alternate Specimen
Serum: Red top
Minimum Volume
0.5 mL
Transport Temperature
Refrigerated
Rejection Criteria
Gross hemolysis
Stability
Room temperature: 48 hours
Refrigerated: 7 days
Frozen: 30 days
Refrigerated: 7 days
Frozen: 30 days
Methodology
Chemiluminescence Immunoassay
Reference Range
<9.80
Performing Laboratory
Quest
New York DOH Approval Status
Yes