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HelpTest Code B-12 Vitamin B12
Synonyms/Keywords
Vitamin B-12, B12, Cyanocobalamin
Specimen Requirements
| Fasting Required | Specimen Type | Preferred Container/Tube | Acceptable Container/Tube | Specimen Volume | Specimen Minimum Volume (allows for 1 repeat) |
Pediatric Minimum Volume (no repeat) |
|---|---|---|---|---|---|---|
| No | Plasma/Serum | Lithium Heparin Plasma Separator Tube (PST) | Lithium Heparin Green Top Tube (GTT), Serum Separator Tube (SST), Red Top Tube (RTT) | 1 mL | 0.5 mL | 0.3 mL |
Collection/Processing Instructions
GTT/RTT- physically separate plasma or serum from contact with cells as soon as possible or before transport.
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Plasma/Serum | Ambient | 8 hours |
| Refrigerated | 24 hours | |
| Frozen | >24 hours |
Rejection Criteria
Slight hemolysis, Marked Icterus
Interferences
For testing performed at Weston: High doses of exogenous biotin (also termed Vitamin B7, Vitamin H or Coenzyme R) may interfere with this assay. It is recommended that patients refrain from consuming any multivitamin or supplement containing biotin for at least 72 hours prior to collection of a blood sample.
Interpretations
For normal values: B12 immunoassays may rarely be falsely normal in patients with deficiency. If the clinical suspicion remains high (e.g. unexplained significant macrocytic anemia), consider ordering serum methylmalonic acid).
For low values: B12 immunoassays have suboptimal diagnostic specificity. Although a trial of B12 supplementation may be reasonable, confirmatory testing with serum methylmalonic acid is recommended. Keep in mind that modest elevations in MMA are common with even mild renal insufficiency and in older adults due to decreased renal clearance. True deficiency usually has very high MMA values.
Reference Range Information
| Performing Location | Reference Range |
|---|---|
| Weston | 160-1000 pg/mL |
| Marshfield | 146-914 pg/mL |
Marshfield Labs Performing Department
Marshfield Labs Chemistry
Performing Information
| Performing Location | Day(s) Test Performed | Analytical Time | Methodology/Instrumentation |
|---|---|---|---|
| Marshfield | Monday through Sunday | Less than 2 hours | Immunoenzymatic Assay/Beckman Coulter DXI |
CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 82607 |
Outreach CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 82607 |
Ordering Applications
| Ordering Application | Description |
|---|---|
| Cerner | Vitamin B-12 |