The Vitamin B6 plasma blood test measures the levels of pyridoxal 5′-phosphate (PLP), the active form of vitamin B6, in the bloodstream. Vitamin B6 is a water-soluble vitamin that is important for various functions in the body, including the metabolism of amino acids and the production of neurotransmitters and red blood cells.

The PLP form of vitamin B6 is the biologically active form, and it is involved in over 100 enzymatic reactions in the body. The Vitamin B6 plasma blood test can be used to assess vitamin B6 status and detect deficiencies.

The normal range for PLP levels in the blood is between 5 and 50 ng/mL. Low PLP levels can indicate a deficiency of vitamin B6, which can lead to symptoms such as anemia, skin rashes, neurological problems, and depression. High levels of PLP are not typically a cause for concern, as excess vitamin B6 is excreted in the urine.

Vitamin B6 deficiencies are relatively rare in the general population, but they can occur in individuals with certain medical conditions, such as malabsorption syndromes or chronic alcoholism. Additionally, certain medications can interfere with vitamin B6 absorption and metabolism, leading to deficiency. The Vitamin B6 plasma blood test can be used to diagnose and monitor vitamin B6 deficiency and to guide treatment with vitamin B6 supplements.