4727.0.55.002 - Australian Aboriginal and Torres Strait Islander Health Survey: Users' Guide, 2012-13  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 10/09/2014  First Issue
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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 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 18 years and over, who participated in the National Aboriginal and Torres Strait Islander Health Measures Survey (NATSIHMS) and who 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.

To calculate the folate concentration from the whole blood sample, haematocrit3 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

There is no consensus on the epidemiological cut off reference values for measuring RCF in the blood. As such, no cut off points have been defined in the NATSIHMS.

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 RCF results from other studies using a different test method.

Comparability with other surveys

The NATSIHMS is the first ABS Aboriginal and Torres Strait Islander survey to collect biomedical information. Given it was also the first national level survey (ABS or otherwise) to collect such data for the Aboriginal and Torres Strait Islander population, no comparisons with previous surveys for this population are possible.

However, biomedical data was also collected for all Australians in the 2011-12 National Health Measures Survey (NHMS) and information about comparisons between the NHMS results and those of non-ABS surveys is available from the Comparisons with other Australian surveys section of the Biomedical Results for Chronic Diseases, 2011-12 publication.

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 08/09/2014.
3 Abbott Diagnostics 2009, Abbott Architect SYSMEX XE2100 laboratory manual.



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