Lipemia refers to visible turbidity in serum or plasma caused by elevated triglycerides—typically above 300–400 mg/dL—due to an accumulation of chylomicrons or very low-density lipoprotein (VLDL). It is a common preanalytical variable that can significantly distort laboratory results.
Major Causes
- Dietary: A recent high-fat meal (postprandial state) is the most frequent preanalytical cause.
- Genetic: Familial hypertriglyceridemia, familial combined hyperlipidemia, lipoprotein lipase deficiency, and apoC-II deficiency.
- Metabolic: Uncontrolled diabetes, insulin resistance, obesity, metabolic syndrome, hypothyroidism, nephrotic syndrome, and chronic kidney disease.
- Medications: Corticosteroids, estrogen/oral contraceptives, retinoids, protease inhibitors, beta-blockers, thiazides, and antipsychotics.
- Alcohol: Acute binge or chronic use increases VLDL synthesis.
- Pregnancy: Physiologic hypertriglyceridemia peaks in the third trimester.
Laboratory Interference
- Spectrophotometric assays: Falsely elevated absorbance leads to erroneous results for electrolytes, creatinine, bilirubin, and enzymes.
- Immunoassays: Light scattering disrupts antigen-antibody binding.
- Coagulation studies: Fibrinogen interference.
- Blood gas analysis: Falsely elevated pO₂ when measured via co-oximetry.
Management Strategies
- Preanalytical: Require 10–12 hour fasting; use ultracentrifugation or lipid-clearing agents (e.g., Lipoclear) for urgent samples.
- Clinical: Treat the underlying disorder—glycemic control, lipid-lowering therapy (fibrates, omega-3 fatty acids, statins), and lifestyle modification.
- Acute severe hypertriglyceridemia (>1000 mg/dL): Insulin infusion, heparin, or plasmapheresis to prevent pancreatitis.
