4363.0.55.001 - Australian Health Survey: Users' Guide, 2011-13  
Latest ISSUE Released at 11:30 AM (CANBERRA TIME) 11/12/2013   
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Red Cell Folate (RCF)

Definition

The measurement of Red Cell Folate (RCF), also known as erythrocyte folate, is a good indicator of longer term folate stores in the body due to the life span (120 days) of the red cell.1 In women of child bearing age, there is clear evidence associated with specific levels of RCF in the blood and protection against neural tube defects (NTDs), such as spina bifida in a developing foetus.1 It is for this reason that the current recommendations of folic acid intake for women of child bearing age (16 to 44 years) is 400 μg per day before conception and during the early months of pregnancy.2 Factors affecting the levels of RCF in the body include age, pregnancy, smoking, oral contraceptive use and Vitamin B12 deficiency.

The RCF test measures the amount of RCF circulating in the blood at the time of the test.

Population

RCF results were obtained for persons aged 12 years and over, who participated in the National Health Measures Survey (NHMS) and provided a blood sample. Fasting was not required for this test.

Methodology

A blood sample was collected from participants and RCF levels were measured at the Douglass Hanly Moir (DHM) laboratory.

In the NHMS, ranges of measured RCF levels were presented in the data tables rather than cut off reference values, as there are no internationally recognised cut off points for normal and abnormal results for the general population. For women of child bearing age (16 - 44 years), target reference values for sufficient and insufficient folate levels were sourced from the Daly study.3

In the NHMS, the following definitions were used for RCF levels, for women of child bearing age (16 - 44 years):

  • Sufficient RCF levels ≥906 nmol/L
  • Insufficient RCF levels <906 nmol/L.

To calculate the folate concentration from the whole blood sample, haematocrit4 levels from the laboratory's blood pre-screening process and specific folate measurements were input into the standard RCF formula using the following equation:

RCF (nmol/L) = folate result from RCF machine x 31 x 100
% haematocrit

Further information about the analysis method and machines used to measure RCF levels is available in Excel spreadsheet format in the Downloads page of this product.

Data items

The data items and related output categories for this topic are available in Excel spreadsheet format from the Downloads page of this product.

Interpretation

Points to be considered when interpreting data for this topic include the following:
  • RCF results do not confirm a specific diagnosis without consultation with a health professional.
  • There are a number of different test methods to measure red cell folate levels and each test method may produce different results. The data from this topic should therefore be used with caution when comparing red cell folate results from other studies using a different test method.

Comparability with other surveys

The NHMS is the first ABS survey to collect biomedical data on folate levels.

Folate data has been collected in other non-ABS surveys. However, caution must be taken when interpreting results due to the differences in scope, assay and the instrument used, and any thresholds applied in the final analysis.

ENDNOTES

1 Gibson RS 2005, Principles of Nutritional Assessment, 2nd ed, New York: Oxford University Press.
2 AIHW 2011, Mandatory folic acid and iodine fortification in Australia and New Zealand: baseline report for monitoring, <http://www.aihw.gov.au/WorkArea/DownloadAsset.aspx?id=10737418918&libID=10737418917>, Last accessed 13/11/2013.
3 Daly LE, Kirke PN, Molloy A, Weir DG and JM Scott 1995. Folate levels and neural tube defects. Implications for prevention. Journal of the American Medical Association 274:1698-702.
4 Abbott Diagnostics 2009, Abbott Architect SYSMEX XE2100 laboratory manual.

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