Laboratory Medicine
Test Directory / Folate
Folate
Brown clotted serum, gel barrier
| Test | Folate |
|---|---|
| Common Abbreviations | FOL |
| Profile | Haematinics |
| Tube type | Brown clotted serum, gel barrier |
| Clinical Indication | Used in the investigation of suspected folate deficiency. Low folate intake, malabsorption as a result of gastrointestinal diseases, chronic alcoholism, pregnancy and drugs such as phenytoin are causes of folate deficiency. Folate and B12 deficiency impair DNA synthesis, causing macrocytic anaemias. |
| Specimen Type | Blood |
| Sample type | Serum |
| Minimum Volume | 0.5mL If requesting more than 10 tests please send an additional brown clotted serum sample. |
| Special Precautions | Fasting sample preferred. |
| Stability | 48 hours at 20 - 25°C, 72 hours at 2 - 8°C and 28 days at -20°C. |
| Turnaround Time | Inpatient: 24 hours Outpatient/ GP: 24 hours |
| Laboratory | York and Scarborough |
| Reference Interval | 3.89 - 26.8µg/L (Quoted by the manufacturer) |
| Limitations | Analysis should not be performed on icteric or lipaemic samples. Haemolysis may significantly increase folate values due to high concentrations of folate in red blood cells. Therefore, haemolysed samples are not suitable for analysis. The assay is unaffected by biotin < 86.1 nmol/L or < 21 ng/mL. No interference was observed from rheumatoid factors up to a concentration of 1000 IU/mL. No interference was observed from IgG < 1.6 g/dL; IgA < 0.4 g/dL; IgM < 1.0 g/dL Samples should not be taken from patients receiving therapy with high biotin doses (i.e. > 5 mg/day) until at least 8 hours following the last biotin administration. In vitro tests were performed on 16 commonly used pharmaceuticals. No interference with the assay was found. Samples with extremely high total protein concentrations are not suitable for use in this assay, since they may lead to the formation of protein gel in the assay cup. In rare cases, high titres of antibodies to analyte specific antibodies, streptavidin or ruthenium can occur. 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. |
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