081893: Fatty Acids, Free (Nonester) (2025)

Table of Contents

Test Details Methodology Result Turnaround Time Related Documents Use Custom Additional Information Specimen Requirements Specimen Volume Minimum Volume Container Collection Instructions Stability Requirements Reference Range Storage Instructions Patient Preparation Causes for Rejection LOINC® Map

Test Number 081893Test number copied

CPT 82725

Synonyms

Free Fatty Acids
Nonesterified Free Fatty Acids

Share
Print Include LOINC® in print

Test Details
Specimen Requirements
LOINC®

Test Details

Methodology

Spectrophotometry

Result Turnaround Time

3 - 6 days

Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.

Use

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.

Custom 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.

Specimen Requirements

Specimen

Serum, frozen

Volume

1 mL

Minimum Volume

0.2 mL (Note: This volume does not allow for repeat testing.)

Container

Red-top tube or gel-barrier tube

Collection Instructions

After clotting, separate serum and freeze immediately following centrifugation. Serum is the specimen of choice. 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. Transfer specimen to a plastic transport tube before freezing. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.

Stability Requirements

Temperature	Period
Room temperature	4 hours
Refrigerated	1 day
Frozen	105 days
Freeze/thaw cycles	Stable x6

Reference Range

See table.

Age	Male (mEq/L)	Female (mEq/L)
0 to 30 d	0.0−0.8	0.0−0.8
1 to 6 m	0.0−0.9	0.0−1.1
7 m to 1 y	0.1−2.2	0.2−1.9
2 to 5 y	0.2−2.3	0.1−2.8
6 to 12 y	0.0−1.2	0.0−1.2
13 to 30 y	0.0−0.8	0.0−1.0
31 to 70 y	0.1−0.9	0.1−1.1
71 to 80 y	0.2−0.7	0.1−1.1
>80 y	0.1−0.9	0.1−0.9

Storage Instructions

Freeze. The level of NEFA will increase in serum as it is allowed to stand at room temperature due to enzymatic action.

Patient Preparation

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.

Causes for Rejection

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.

LOINC® Map

Order Code	Order Code Name	Order Loinc	Result Code	Result Code Name	UofM	Result LOINC
081893	Fatty Acids, Free (Nonester)	15066-4	081893	Fatty Acids, Free (Nonester)	mEq/L	15066-4
Order Code	081893
Order Code Name	Fatty Acids, Free (Nonester)
Order Loinc	15066-4
Result Code	081893
Result Code Name	Fatty Acids, Free (Nonester)
UofM	mEq/L
Result LOINC	15066-4