What is the Triene/Tetraene Ratio?

The Triene/Tetraene (T/T) ratio is another marker for essential fatty acid status. It is calculated as the ratio of Mead acid to arachidonic acid. This ratio, combined with measurements of the essential fatty acids and Mead acid, gives a more complete picture of the degree and nature of fatty acid deficiency. An elevated ratio shows a relative excess of triene (3 double bonds) compared to tetraene (4 double bonds), which results from essential fatty acid deficiency.

Essential fatty acid deficiency 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.

General Biochemical and Physical Signs and Symptoms of Essential Fatty Acid Deficiency:


  • Elevated Triene/Tetraene (T/T) ratio
  • Elevated liver function tests
  • Hyperlipidemia
  • Thrombocytopenia
  • Altered platelet aggregation


  • Dry, scaly rash
  • Hair loss
  • Hair depigmentation
  • Poor wound healing
  • Growth restriction in children
  • Increased susceptibility to infection

Normal ranges:

  • < or =31 days: 0.017-0.083
  • 32 days-17 years: 0.013-0.050
  • > or =18 years: 0.010-0.038

High values:

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



The information on is NOT intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice.

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