Test Directory

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.

Specimen Type: Serum

Collection Container: Gold Top, Serum Separator

Alternate Collection Container: Red Top, Plain

Desired Specimen Volume: 1 mL

1. Collect a gold top, serum separator tube via venipuncture

1. Allow specimen to clot. Separate serum from cells immediately after centrifugation.
2. Transfer 1 mL of serum to a LabCorp PP transpak frozen purple tube and freeze immediately.
3. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.

Sample 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.

Transport to the laboratory frozen. 

• 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 NEFA test.

See patient report.

Heparin must not be used nor should the patient be on heparin therapy. The NEFA level in serum will increase as it remains at room temperature due to enzymatic action..

• Free Fatty Acids
• Nonesterified Free Fatty Acids