Very Long Chain Fatty Acids

There are no preparation instructions.

The following is a list of what is included in the item above. Click the test(s) below to view what biomarkers are measured along with an explanation of what the biomarker is measuring.


Discriminant Function

Docosanoic Acid, C22


Hexacosanoic Acid, C26

Phytanic Acid

Pristanic Acid

Ratio C24/C22

Ratio C26/C22

Ratio Pristanic/Phytanic

Tetracosanoic Acid, C24

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The Very Long Chain Fatty Acids test contains 1 test with 11 biomarkers.

Very Long Chain Fatty Acids (VLCFAs) Analysis 

Clinical Significance

The analysis of Very Long Chain Fatty Acids (VLCFAs) plays a critical role in the diagnostic process of various genetic metabolic disorders. Peroxisomes, cellular organelles pivotal to numerous metabolic pathways, including the synthesis of certain phospholipids (plasmalogens) and bile acids, also oversee the catabolism of VLCFAs, phytanic acid, and pristanic acid. When peroxisomes fail to function correctly due to genetic mutations, it can lead to the accumulation of these substances, causing cellular and tissue damage. The VLCFA test measures the levels of these fatty acids in the blood, aiding in the diagnosis of peroxisomal disorders.

Defective peroxisomal functioning can lead to a range of disorders, each with varying degrees of severity and symptoms. These include:

  • Zellweger Spectrum Disorders (ZSDs): A group of autosomal recessive disorders characterized by impaired peroxisomal biogenesis. Symptoms can range from severe, such as in Zellweger syndrome, to milder forms like Heimler syndrome.
  • X-linked Adrenoleukodystrophy (X-ALD) and X-linked Adrenomyeloneuropathy (X-AMN): These are characterized by the accumulation of VLCFAs in the brain and adrenal cortex, leading to neurodegeneration and adrenal insufficiency.
  • Refsum Disease: Caused by the accumulation of phytanic acid due to a deficiency in the enzyme phytanoyl-CoA hydroxylase. It affects the nervous system and the skin.
  • 2-Methylacyl-CoA Racemase Deficiency: A disorder that affects the metabolism of certain fats, leading to neurological problems and other symptoms.

Who Can Benefit

The VLCFA analysis can benefit:

  • Individuals Exhibiting Symptoms: Those showing signs of neurological decline, adrenal insufficiency, or other symptoms consistent with peroxisomal disorders.
  • Family Members of Affected Individuals: As many of these disorders are inherited, testing can identify carriers or diagnose affected family members early.
  • Neonatal Screening: Early identification in newborns can lead to timely interventions, potentially mitigating the progression of symptoms.

Clinical Utility

  • Diagnostic Clarification: Distinguishing between different peroxisomal disorders based on the pattern of VLCFA accumulation.
  • Treatment Monitoring: Evaluating the effectiveness of dietary interventions or other treatments aimed at reducing VLCFA levels.
  • Genetic Counseling: Providing families with information about the inheritance patterns, risks to future children, and implications for family planning.

How It Helps

The VLCFA test offers a non-invasive method to aid in the diagnosis of peroxisomal disorders. By quantifying the levels of VLCFAs in the blood, healthcare providers can:

  • Make a differential diagnosis among various peroxisomal disorders, each of which may require a distinct treatment approach.
  • Initiate early interventions, such as dietary modifications or gene therapy, where available, to manage symptoms and potentially slow disease progression.
  • Provide families with accurate diagnoses, enabling informed decisions regarding family planning and the management of the disorder.

In conclusion, VLCFA analysis is a vital tool in the diagnosis and management of peroxisomal disorders, offering hope and direction for affected individuals and their families through early detection and intervention strategies.

Patient Preparation 

Avoid alcohol for 24 hours prior to collection. Draw sample in the morning following overnight fasting (12-14 hours)

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