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.
Patient Preparation
Sample should be collected in the early morning after a 12-hour fast. Blood for the nonester 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 nonester will be elevated and not directly comparable to a normal range derived from fasting normal controls.
Collect
Gel-barrier tube or red-top tube
Specimen Preparation
If a red-top tube is used, transfer 1.0 mL separated serum to a plastic transport tube.
Unacceptable Conditions
Heparin plasma received; specimen not frozen. NOTE: Heparin 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 nonester test.
Storage/Transport Temperature
Frozen
Stability (from collection to initiation)
After separation from cells: Room temperature: 4 hours; Refrigerated: 1 day; Frozen: 105 days (avoid freeze/thaw cycles)
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.
Patient Preparation
Sample should be collected in the early morning after a 12-hour fast. Blood for the nonester 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 nonester will be elevated and not directly comparable to a normal range derived from fasting normal controls.
Collect
Gel-barrier tube or red-top tube
Specimen Preparation
If a red-top tube is used, transfer 1.0 mL separated serum to a plastic transport tube.
Unacceptable Conditions
Heparin plasma received; specimen not frozen. NOTE: Heparin 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 nonester test.
Storage/Transport Temperature
Frozen
Stability (from collection to initiation)
After separation from cells: Room temperature: 4 hours; Refrigerated: 1 day; Frozen: 105 days (avoid freeze/thaw cycles)
