Chemical Pathology


  • Very long chain fatty acid (VLCFA) analysis is indicated in the differential diagnosis of peroxismal disorders.
  • Peroxisomes are intracellular organelles which contain the enzymes required for β-oxidation of VLCFA (fatty acids with chain lengths of more than 22 carbon atoms).
  • VLCFA can be increased in disorders such as adrenoleukodystrophy, Refsum's and Zellweger syndrome. Pristanic and phytanic acid are also assayed to assist in the differential diagnosis of these very rare conditions.
  • These patients may present with profound neurological and metabolic problems in infancy, or neurological and adrenal problems in childhood and adult life, depending on the disease.

Sample requirements

  • Fasting samples preferred, sent promptly to the laboratory

For adults, blood taken into a 4mL EDTA tube (lithium heparin or plain serum also suitable)

EDTA with cap

For children, blood taken into a 2mL lithium heparin tube (minimum 500uL plasma required)

2ml lithium heparin BD paediatric tube


Do not store. Send at ambient temperature to the laboratory on the same day as sample collection, as promptly as possible.

Required information

Relevant clinical details, including details of clinical presentation.

Turnaround times

Samples are sent for analysis at the North Bristol NHS Trust with a result expected back within 2 weeks.

Reference ranges

VLCFA Reference range Units
C26 0.33 - 1.39 µmol/L
C26:C22 <0.030
C24:C22 0.32 - 1.07
Pristanic acid <3.0 µmol/L
Phytanic acid <16 µmol/L