Normal vitamin B9 (folic acid) level in the blood

Vitamin B9, also known as folate or folic acid, plays a crucial role in various bodily functions. Folate refers to the natural form of vitamin B9 found in foods, while folic acid is the synthetic form commonly used in supplements and fortified foods.

Vitamin B9 is essential for the production of red blood cells (RBCs) and white blood cells (WBCs). It also plays a vital role in brain health, DNA synthesis, and cell division. A deficiency in vitamin B9 can lead to a reduced number of RBCs, resulting in anemia.

Folate is absorbed from the diet in the small intestine (primarily in the jejunum), and any excess is excreted through the urine.

Foods rich in folate include green leafy vegetables (such as spinach, lettuce, cabbage, and broccoli), asparagus, fruits (like citrus and kiwi), dairy products, and animal liver or kidney.

Vitamin B9 is especially important during pregnancy, as it supports the development of the fetus. A deficiency during pregnancy can lead to neural tube defects, so pregnant women are often advised to take folic acid supplements.

Folic acid and vitamin B12 are interrelated in methionine synthesis. A deficiency in either vitamin can disrupt this pathway, leading to similar clinical symptoms. Additionally, due to their shared metabolic role, a deficiency in vitamin B12 impairs the incorporation of folate into erythrocytes (red blood cells), causing low intraerythrocytic folate levels even when dietary folate intake is adequate. For these reasons, it is often necessary to measure the levels of both vitamins in clinical evaluations. Treatment depends on identifying which vitamin is deficient.

The vitamin B9 (folic acid) blood test is primarily used to evaluate cases of macrocytic anemia, a type of anemia characterized by low hemoglobin levels and unusually large red blood cells (RBCs).

This test provides valuable information when diagnosing macrocytic anemia, which is marked by:

• Anemia (low level of hemoglobin in the blood)
• Macrocytosis or an increased mean corpuscular volume (MCV) greater than 100 fL

Folate (vitamin B9) and vitamin B12 (cobalamin) levels are usually tested together, as the diagnosis of macrocytic anemia requires both measurements to determine the underlying cause.

In addition, the test is also used to monitor the effectiveness of therapy for low folate levels.

Each laboratory must establish its own normal ranges for vitamin B9 (folic acid) in the blood. These ranges depend on the makeup of the local population, the technologies used and the accuracy of the measurement. There may be also slight differences in the normal levels, according to age, gender, race or ethnic origin, geographic region, diet, type of sample and other relevant status.

Your doctor will study the results along with your medical record, screenings, physical condition, symptoms and any other relevant information about your situation.

In elderly people, the average normal range is usually lower.

There is also another test called the RBC (red blood cell) folate concentration test, which measures folate levels within RBCs instead of in the plasma. The previously mentioned test measures folate (vitamin B9) in the blood plasma. The normal range for RBC folate concentration is 125 to 600 ng/mL.

The following values are considered to be normal values:

IMPORTANT: These levels are expressed in ng/ml. They are an example of a healthy adult of about 45 years old with no known disease and not taking any medication. The ranges can be different depending on the laboratory or on your personal circumstances.