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Folate, serum

Item Value
Test Update Information Effective 1/10/18, Serum Folate will be the routine test available for diagnosing folate deficiency instead of RBC Folate. If RBC Folate is required, order as MOLT for sendout testing to ARUP Lab (Collect Lavender (EDTA) or pink (K2EDTA).
Available Stat? No
Test code SFOL
Performed by China Basin Chemistry
In House Availability Tuesday and Friday (day shift)
Method Chemiluminescent Microparticle Immunoassay (Abbott Architect i2000)
Patient Preparation An overnight fast is recommended prior to specimen collection for reference ranges to apply.
Container type Gold top or Red top
Amount to Collect 1 mL blood
Sample type Serum
Preferred volume 0.3 mL serum
Min. Volume 0.15 mL serum
Processing notes Aliquot and freeze serum at -20°C.
Units ng/mL
Normal range
< 2 ng/mL LOW. Consistent with folate deficiency
2 - 4 ng/mL BORDERLINE. Additional testing may be indicated depending on the clinical circumstances.
> 4 ng/mL NORMAL. Suggests folate is not deficient, unless the individual has recently consumed a folate-containing meal or supplement. In such cases, RBC folate can be obtained. The RBC folate level is not needed in routine testing because it does not provide additional information and more costly to obtain.

If patient was not fasting, the normal ranges may not apply.

Reference range adopted from https://www.uptodate.com and verified in-house with lab donor samples.
Synonyms Folic Acid
Stability Refrigerated (2-8°C): 7 days
Frozen (-10°C or colder): 30 days

Avoid more than 3 freeze/thaw cycles.
Turn around times 1 - 5 days
Additional information To convert ng/mL to nmol/L (SI units) multiply by 2.265.

The ARCHITECT Folate assay is standardized to the World Health Organization (WHO) Serum Folate International Standard 03/178.

Serum specimens from patients with renal impairment or failure (including dialysis patients) may exhibit varying degrees of falsely depressed folate values. Therefore to evaluate patients with renal impairment or failure who also exhibit low folate levels, it is recommended that low ARCHITECT Folate values be confirmed by an alternate folate method.

Methotrexate, aminopterin, and folinic acid (Leucovorin) are chemotherapeutic agents whose molecular structures are similar to folate. These agents cross react with folate binding protein in folate assays. Do not use the ARCHITECT Folate assay or other assays employing folate binding proteins for patients using these drugs.

If RBC Folate is required, order as MOLT for sendout testing to ARUP Lab (Collect Lavender (EDTA) or pink (K2EDTA).
CPT coding 82746
LOINC code 2284-8
Last Updated 12/13/2017 2:37:05 PM
Entry Number 1813
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