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Lab Manual for Moffitt-Long and Mount Zion

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Triene/Tetraene Ratio

Item Value
Approval req'd? No
Available Stat? No
Test code EFA
Performed by Mayo
Sendout? Yes
Method Gas Chromatography-Mass Spectrometry (GC-MS) Stable Isotope Dilution Analysis
Patient Preparation Patient must fast for 12-14 hours and should not consume any alcohol for 24 hours before the specimen is drawn.
Collection Instructions Include patient age and information regarding treatment, family history, and tentative diagnosis on requisition.

Transport to laboratory immediately after collection for processing.
Container type Red top or Gold top
Amount to Collect 1 mL blood
Sample type Serum
Preferred volume 0.5 mL serum
Min. Volume 0.2 mL serum
Processing notes Spin down sample immediately and freeze serum.
Normal range
Synonyms Fatty acid profile of lipids; Essential Fatty Acid Profile
Stability Frozen 3 months
Turn around times 7-9 days
Additional information Fats are important sources of energy for tissues and are important for the function and integrity of cellular membranes. Deficiencies are commonly caused by inadequate dietary intake of lipids due to an unbalanced diet or long-term parenteral nutrition, or by intestinal malabsorption, which is common in conditions such as cystic fibrosis and irritable bowel syndrome. Deficiencies can also be caused by an impairment of biomolecular transformations among fatty acids, such as linoleic acid to arachidonic acid. Linoleic and linolenic acids cannot be made by the body and are essential components of the diet (ie, essential fatty acids).

The major clinical manifestations associated with essential fatty acid deficiency (EFAD) include dermatitis, increased water permeability of the skin, increased susceptibility to infection, lowered resistance to irradiation injury, impaired wound healing, hemolytic anemia, thrombocytopenia, fatty infiltration of the liver, elevated hepatic enzymes, and impaired chylomicron synthesis. Treatment of EFAD depends on the source of the deficiency and may include supplementation of essential fatty acids, linoleic acid and alpha-linolenic acid.

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 (C18:2w6) and alpha-linolenic acid (C18:3w3). It can also be detected by increases in the ratio triene/tetraene ratio (Holman index): (eicosatrienoic [mead] acid [C20:3w9]/arachidonic acid [C20:4w6]).

Excess dietary fatty acids have also been linked to the onset of cardiovascular disease. The dietary contents of saturated, monounsaturated, or polyunsaturated fatty acids influence the concentration of cholesterol in low-density and high-density lipoproteins, and consequently the development of atherosclerosis. Regular consumption of, or supplementation with, polyunsaturated fatty acids may have a beneficial effects on long-term cardiovascular prognosis due to their anti-inflammatory and possibly antiarrhythmic effects. Elevated levels of C18:2w6 can contribute to overproduction of the proinflammatory 2-series local hormones.
CPT coding 82544-90
Last Updated 8/21/2012 10:42:33 AM
Entry Number 950
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