Vitamin B6 (Pyridoxal) in Serum/Plasma

Why This Test Might Be Ordered

Your doctor may recommend this test if you have symptoms like fatigue, nerve pain, depression, or unusual cravings for foods high in vitamin B6 (such as legumes, nuts, or fortified cereals). It may also be checked in cases of suspected vitamin deficiencies, certain medical conditions, or after treatments that can deplete vitamin B6 levels, such as chemotherapy or long-term use of certain medications.

What to Expect Before the Test

No special preparation is usually needed, but your doctor may ask you to stop certain medications (like some anticonvulsants) for a few days before testing. You’ll provide a blood sample, typically drawn from a vein in your arm.

Your results will show the concentration of vitamin B6 in your blood. While reference ranges vary by lab, low levels may indicate a deficiency, while very high levels could suggest overconsumption or certain medical conditions.

Low vitamin B6 levels may cause symptoms like weakness, numbness, or irritability. High levels are less common but could be linked to specific health conditions or excessive intake.

Common Causes of Abnormal Results

Vitamin B6 deficiency can result from poor diet, malabsorption issues (like celiac disease), certain medications, or conditions affecting nutrient absorption. Overly high levels may occur with long-term supplements or rare genetic disorders.