Free Fatty Acids, Plasma

Diagnostic Use

Measurement of non-esterified fatty acids (NEFA) is used in the investigation of hypoglycaemia in infants and children. The result is interpreted in conjunction with the results of glucose and ketones. Please note free fatty acids and essential fatty acids are different tests.

Elevated serum concentrations of NEFA are also associated with cardiovascular disease, metabolic syndrome, obesity, and type 2 diabetes mellitus. NEFA are causally linked with insulin resistance and inflammation of vascular endothelium, however they are not routinely measured for this purpose as other well-established lipid markers of cardiovascular disease risk are available. Abnormally high levels of free fatty acids are associated with uncontrolled diabetes mellitus and with conditions that involve excessive release of a lipoactive hormone such as epinephrine, norepinephrine, glucagon, thyrotropin, and adrenocorticotropin.

Department

Lipids/Trace Metals

Delphic Registration Code

FFA

Laboratory Handling

Phlebotomy

Sample is not to be shared. Fasting specimen preferred.

Separating

Specimens must be collected on ice and the plasma separated from the red cells within 30 minute of collection and immediately frozen.

Laboratory

Gross haemolysis reject, gross lipemia reject, gross icterus reject

Test Adds

Frozen 7 days

Synonyms

Fatty Acids - free
Fatty Acids - non esterified
FFA
NEFA
Non-Esterified Fatty Acids

Turnaround Time

5 days

Test Code

4289

Specimen Type

• Plasma

Specimen Requirements

Tube/Container Type:

Preferred

• EDTA (Lavender Cap)

Preferred Sample Volume (ml)

5

No of Samples Required

1

Paediatric Specimen Requirements

Tube/Container Type:

Preferred

• EDTA (Lavender Cap)

Preferred Sample Volume (ml)

1

Minimum Sample Volume (ml)

1

Interferences

Patients receiving therapeutic heparin are unsuitable for this analysis. Heparin causes the release of free fatty acids by stimulating the activity of lipoprotein lipase, which causes triglycerides associated with blood lipoproteins to release free fatty acids.

Additional Specimen Information

Delays in the processing of the sample leads to an increase in free fatty acid levels due to lipolysis of the triglycerides by lipase.

Aliquot Instructions

Sample Type

• Plasma

Minimum Volume (ml)

0.25

Transport to Lab

Frozen

Interpretation

In the setting of hypoglycaemia in infants and children, a raised free fatty acid result indicates a lipolytic response, which is appropriate if the patient is hypoglycaemic. However, if this is paired with a low beta-hydroxybutyrate, this may indicate a fatty acid oxidation defect in the setting of hypoglycaemia.

Reference Intervals

<0.6 mEq/L

Test Method

Enzymatic determination.acyl-CoA synthatase substrate.

Non-Funded Test Cost

$73.47 (Exclusive of GST)

Billing Code

4289

Contact Information

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