Biochemistry
Haematology and Transfusion
Clinical Microbiology (Including Virology)
Cellular Pathology
General Information
Immunology
Molecular Pathology
Preferred Sample Type
Suitable Specimen Types
SerumFolate
Specimen Volume
5-10 ml vacutainer (minimum sample volume 75 uL)Sample Preparation
Turnaround Time
1 daySample Processing In Laboratory
UsualSample Stability
Serum is stable at 2-8˚C for up to 48 hours. For longer periods (up to 28 days), store serum frozen at -20˚C.
General Information
Folate and folic acid are forms of a water-soluble B vitamin. Folate occurs naturally in food. Folic acid is the synthetic form of this vitamin that is found in supplements and some fortified foods. Folate plays an important role in the formation of cofactors for certain vital metabolic reactions, and are also essential components in the production of DNA. Folate measurement is often clinically indicated, since left untreated, folate deficiency can lead to megaloblastic anaemia and a deficiency in pregnancy has been associated with neural tube defects in the foetus. It is important to measure B12 and folate in all patients suspected of having low levels of either vitamin. Folate deficiency usually arises from inadequate intake, malabsorption or increased requirements (pregnancy, lactation, or excessive alcohol consumption). Signs of folic acid deficiency are often subtle. Diarrhoea, loss of appetite, and weight loss can occur. Additional signs are weakness, macroglossia, headaches, heart palpitations, irritability, and behavioural disorders.
Patient Preparation
For patients receiving therapy with high biotin doses (i.e. >5 mg/day), samples should be taken at least 8 hours post dose. It is contraindicated to measure samples of patients receiving therapy with certain pharmaceuticals, e.g. methotrexate or leucovorin, because of the cross‑reactivity of folate binding protein with these compounds. Samples with extremely high total protein concentrations (e.g. patients suffering from Waldenström’s macroglobulinemia) are not suitable for use in this assay. Haemolysis may significantly increase folate values due to high concentrations of folate in red blood cells. Therefore, hemolyzed samples are not suitable for use in this assay. In rare cases, interference due to extremely high titers of antibodies to streptavidin and ruthenium can occur. These effects are minimized by suitable test design.
Notes
Haemolysis may significantly increase folate values due to high concentrations of folate in red blood cells. Therefore, hemolyzed samples are not suitable for use in this assay. Samples with extremely high total protein concentrations (e.g. patients suffering from Waldenström’s macroglobulinemia) are not suitable for use in this assay. In rare cases, interference due to extremely high titers of antibodies to streptavidin and ruthenium can occur. These effects are minimized by suitable test design.
Reference Range
3.1 - 20.5 µg/L
Source of Reference Range
Abbott DiagnosticsSpecifications
-
EQA Status:
NEQAS
- EQAS Scheme: Yes