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Test Code
SynonymsFree Fatty Acids; Nonesterified Free Fatty Acids
Container TypeSerum separator tube (gold, brick, SST, or corvac)
Supply Item Numberpicture1467
Specimen TypeSerum
Preferred Volume1 mL
Emergency Minimum Volume0.2 mL
Patient PrepSample should be collected in the early morning after a 12-hour fast. Blood for the NEFA procedure should be collected after an overnight fast because the level of circulating nonesterified fatty acids is strongly influenced by food ingestion. If the patient has not properly fasted, the determined level of NEFA will be elevated and not directly comparable to a normal range derived from fasting normal controls.
Collection ProcedureHeparin must not be used nor should the patient be on heparin therapy.
Specimen ProcessingAfter cllotting separate serum from cells and transfer to a standard PAML aliquot tube and freeze immediately.
Store and TransportFrozen - Separate samples must be submitted when multiple tests are ordered.
Unacceptable ConditionHeparin plasma received; specimen not frozen
Alternate SpecimensRed top tube (plain)
LimitationsHeparin is known to stimulate the activity of lipoprotein lipase, which acts upon triglycerides associated with blood lipoproteins to release free or nonesterified fatty acids. For this reason, blood collected from patients receiving therapeutic heparin or blood collected in heparinized containers is not suitable for the NEFA test. The NEFA level in serum will increase as it remains at room temperature.
CPT Codes82725
Interface Order Code82725.Z1
Billing CodeFATTYL
Reference Ranges
Fatty Acids, Free (Nonester)0.1-0.6mEq/L
NotesUse: Knowledge of the level of nonesterified fatty acids (NEFA) in blood plasma can be helpful in the diagnosis and management of certain diseases and disorders of metabolism and in the evaluation of prospective causes of hyperlipoproteinemia. A disorder of disease that causes excessive release of a lipoactive hormone (epinephrine, ACTH, GH, etc) can induce an elevation of blood level of fatty acids. A sustained release of fatty acids from adipose cells in excess of energy needs can contribute to the development of secondary hyperlipoproteinemia.

Additional Information: Plasma or serum NEFA is the portion of the total fatty acid pool that circulates in immediate readiness for metabolic needs. NEFA can be absorbed readily by muscle, heart, brain, and other organs as an energy source whenever insufficient quantities of glucose limit the usual carbohydrate energy source. In all probability, both glucose and NEFA are simultaneously taken up from the blood, even under normal conditions. When blood glucose levels are high, the NEFA level falls, and vice versa, emphasizing the reciprocal withdrawal of stored energy, under the simultaneous control of insulin and epinephrine. In acute starvation, the NEFA level may rise as much as three times the normal values.

Interface Codes
typeorder codetest descriptionresult coderesult descriptionunitsdecimal placesloinc code
r82725.Z1Fatty Acids, Free (Nonester)82725.Z1Fatty Acids, Free (Nonester)mEq/L115066-4