PLASMA AMINO ACID

Normal total plasma free amino acids typically range about 2–4 mmol/L (≈2000–4000 µmol/L). Individual amino acid concentrations vary widely: some (e.g., glycine, alanine) are tens to a few hundred µmol/L, while others are single-digit to low-double-digit µmol/L. Reference ranges depend on fasting status, age and lab methods; abnormal patterns need clinical interpretation.

An amino acid blood test measures concentrations of individual amino acids in the bloodstream. It detects abnormalities from inborn metabolic disorders (e.g., phenylketonuria, maple syrup urine disease), nutritional deficiencies, malabsorption, liver or kidney dysfunction, and catabolic states. Results help diagnose metabolic or neurological symptoms, guide dietary or supplement therapy, and monitor treatment response in metabolic disorders or critical illness.

A plasma amino acid panel identifies inherited and acquired disorders of amino acid metabolism and transport. Examples include phenylketonuria, maple syrup urine disease, homocystinuria, tyrosinemia, nonketotic hyperglycinemia, urea‑cycle disorders (citrullinemia, ornithinemia, argininosuccinic aciduria), Hartnup disease and lysinuric protein intolerance. It can also indicate liver disease, malnutrition, or increased protein catabolism when patterns are abnormal.

Yes. Blood plasma contains free amino acids and protein molecules such as albumin. Free amino acids come from digestion and protein turnover, circulate to supply tissues for protein synthesis, energy metabolism and gluconeogenesis, and are measurable in clinical tests. Plasma amino acid levels reflect diet, liver and kidney function and metabolic state; abnormalities can indicate nutritional or metabolic disorders.

Amino acid deficiency can cause fatigue, muscle weakness, loss of muscle mass, slowed growth in children and poor wound healing. Other signs include hair loss, brittle nails, dry or inflamed skin, mood changes (irritability or depression), concentration and memory problems, frequent infections from weakened immunity, swelling (edema) and delayed recovery from illness.

A plasma blood test analyzes the liquid portion of blood after cells are removed to measure substances such as electrolytes, hormones, proteins, antibodies, clotting factors, lipids and glucose. It’s used to assess organ function, diagnose infections and immune conditions, monitor anticoagulant therapy, detect inflammation or metabolic disorders, and guide treatment decisions. Plasma is also used for certain transfusions and specialized laboratory assays.