Test ID: FAPEP    
Fatty Acid Profile, Essential, Serum

Evaluating the nutritional intake and intestinal absorption of essential fatty acids

Identifying deficiency of essential and other nutritionally beneficial fatty acids

Monitoring treatment of patients with essential fatty acid deficiencies who are receiving linoleic acid (C18:2w6) and alpha-linolenic acid (C18:3w3)

Fats are important sources of energy for tissues and for the function and integrity of cellular membranes. Deficiencies are commonly caused by inadequate dietary intake of lipids due to an unbalanced diet, long-term parenteral nutrition, or by intestinal malabsorption. Linoleic acid, an omega-6 fatty acid, and alpha-linolenic acid, an omega-3 fatty acid, are considered essential fatty acids in that they cannot be made by the body and are essential components of the diet.

The major clinical manifestations associated with essential fatty acid deficiency (EFAD) include dermatitis, increased water permeability of the skin, increased susceptibility to infection, and impaired wound healing. Biochemical abnormalities may be detected before the onset of recognizable clinical manifestations. EFAD can be detected by diminished levels of the essential fatty acids linoleic acid and alpha-linolenic acid, as well as by increases in the triene:tetraene ratio.

Excess dietary fatty acids have been linked to the onset of cardiovascular disease. Elevated levels of linoleic acid can contribute to overproduction of the proinflammatory 2-series local hormones.

Lauric Acid, C12:0

<1 year: 6-190 nmol/mL

1-17 years: 5-80 nmol/mL

> or =18 years: 6-90 nmol/mL

Myristic Acid, C14:0

<1 year: 30-320 nmol/mL

1-17 years: 40-290 nmol/mL

> or =18 years: 30-450 nmol/mL

Hexadecenoic Acid, C16:1w9

<1 year: 21-69 nmol/mL

1-17 years: 24-82 nmol/mL

> or =18 years: 25-105 nmol/mL

Palmitoleic Acid, C16:1w7

<1 year: 20-1,020 nmol/mL

1-17 years: 100-670 nmol/mL

> or =18 years: 110-1,130 nmol/mL

Palmitic Acid, C16:0

<1 year: 720-3,120 nmol/mL

1-17 years: 960-3,460 nmol/mL

> or =18 years: 1,480-3,730 nmol/mL

Gamma-Linolenic Acid, C18:3w6

<1 year: 6-110 nmol/mL

1-17 years: 9-130 nmol/mL

> or =18 years: 16-150 nmol/mL

Alpha-Linolenic Acid, C18:3w3

<1 year: 10-190 nmol/mL

1-17 years: 20-120 nmol/mL

> or =18 years: 50-130 nmol/mL

Linoleic Acid, C18:2w6

< or =31 days: 350-2,660 nmol/mL

32 days-11 months: 1,000-3,300 nmol/mL

1-17 years: 1,600-3,500 nmol/mL

> or =18 years: 2,270-3,850 nmol/mL

Oleic Acid, C18:1w9

<1 year: 250-3,500 nmol/mL

1-17 years: 350-3,500 nmol/mL

> or =18 years: 650-3,500 nmol/mL

Vaccenic Acid, C18:1w7

<1 year: 140-720 nmol/mL

1-17 years: 320-900 nmol/mL

> or =18 years: 280-740 nmol/mL

Stearic Acid, C18:0

<1 year: 270-1,140 nmol/mL

1-17 years: 280-1,170 nmol/mL

> or =18 years: 590-1,170 nmol/mL

EPA, C20:5w3

<1 year: 2-60 nmol/mL

1-17 years: 8-90 nmol/mL

> or =18 years: 14-100 nmol/mL

Arachidonic Acid, C20:4w6

<1 year: 110-1,110 nmol/mL

1-17 years: 350-1,030 nmol/mL

> or =18 years: 520-1,490 nmol/mL

Mead Acid, C20:3w9

< or =31 days: 8-60 nmol/mL

32 days-11 months: 3-24 nmol/mL

1-17 years: 7-30 nmol/mL

> or =18 years: 7-30 nmol/mL

Homo-Gamma-Linolenic C20:3w6

<1 year: 30-170 nmol/mL

1-17 years: 60-220 nmol/mL

> or =18 years: 50-250 nmol/mL

Arachidic Acid, C20:0

<1 year: 30-120 nmol/mL

1-17 years: 30-90 nmol/mL

> or =18 years: 50-90 nmol/mL

DHA, C22:6w3

<1 year: 10-220 nmol/mL

1-17 years: 30-160 nmol/mL

> or =18 years: 30-250 nmol/mL

DPA, C22:5w6

<1 year: 3-70 nmol/mL

1-17 years: 10-50 nmol/mL

> or =18 years: 10-70 nmol/mL

DPA, C22:5w3

<1 year: 6-110 nmol/mL

1-17 years: 30-270 nmol/mL

> or =18 years: 20-210 nmol/mL

DTA, C22:4w6

<1 year: 2-50 nmol/mL

1-17 years: 10-40 nmol/mL

> or =18 years: 10-80 nmol/mL

Docosenoic Acid, C22:1

<1 year: 2-20 nmol/mL

1-17 years: 4-13 nmol/mL

> or =18 years: 4-13 nmol/mL

Nervonic Acid, C24:1w9

<1 year: 30-150 nmol/mL

1-17 years: 50-130 nmol/mL

> or =18 years: 60-100 nmol/mL

Triene/Tetraene Ratio

< or =31 days: 0.017-0.083

32 days-17 years: 0.013-0.050

> or =18 years: 0.010-0.038

Total Saturated Acid

<1 year: 1.2-4.6 mmol/L

1-17 years: 1.4-4.9 mmol/L

> or =18 years: 2.5-5.5 mmol/L

Total Monounsaturated Acid

<1 year: 0.3-4.6 mmol/L

1-17 years: 0.5-4.4 mmol/L

> or =18 years: 1.3-5.8 mmol/L

Total Polyunsaturated Acid

<1 year: 1.1-4.9 mmol/L

1-17 years: 1.7-5.3 mmol/L

> or =18 years: 3.2-5.8 mmol/L

Total w3   

<1 year: 0.0-0.4 mmol/L

1-17 years: 0.1-0.5 mmol/L

> or =18 years: 0.2-0.5 mmol/L

Total w6

<1 year: 0.9-4.4 mmol/L

1-17 years: 1.6-4.7 mmol/L

> or =18 years: 3.0-5.4 mmol/L

Total Fatty Acids

<1 year: 3.3-14.0 mmol/L

1-17 years: 4.4-14.3 mmol/L

> or =18 years: 7.3-16.8 mmol/L

Concentrations below the stated reference ranges are consistent with fatty acid deficiencies.

An increased triene:tetraene ratio is consistent with essential fatty acid deficiency.

For nutritional assessment, a 12- to 14-hour fast is required; however, infants or persons suspected of having a fatty acid oxidation disorder should not fast before testing owing to the possibility of acute metabolic decompensation. Instead, collect the specimen after the longest fast possible, just before feeding. In the case of a patient on total parenteral nutrition (TPN), specimen can be drawn as normal.

1. Jeppesen PB, Chistensen MS, Hoy CE, Mortensen PB: Essential fatty acid deficiency in patients with severe fat malabsorption. Am J Clin Nutr 1997;65:837-843

2. McCowen KC, Bistrian BR: Essential fatty acids and their derivatives. Curr Opin Gastroenterol 2005 Mar;21(2):207-215