Rapid Test Determines Vitamin B12 Levels

DAVIS, Calif.Researchers from USDAs Agricultural Research Service (ARS) have developed and tested an improved method for measuring an indicator of the body's stores of B12 in blood that requires only a small amount of blood. Vitamin B12 helps the body perform many vital chores, including forming healthy red blood cells, keeping the brain functioning smoothly, and metabolizing the fats, proteins and carbohydrates in foods we eat.

In the United States, the very young and the elderly are among the groups at risk of becoming B12 deficient. Newborns whose mothers are deficient in the vitamin may begin their lives with low stores of it. The problem may be compounded if these babies are breastfed, because the B12 levels in their mothers milk may be inadequate. If seniors sufficient gastric acid in the stomach they may be unable to absorb enough vitamin B12 from their food. Vitamin B12 is found naturally in meats, fish, poultry, eggs, cheese and yogurt or from B12-fortified foods like breakfast cereals.

The researchers showed that a specimen of only 25 microliters of blood plasma or serumthe equivalent of about one-half of a drop of watercan be analyzed with speed, accuracy, reliability and precision using an analytical technology called UPLC-ESI-MS/MS (ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry).

If the assay is performed using robotics, the sample could perhaps be as small as 5 microliters.

The team built upon earlier work in which scientists elsewhere used an older technology to measure the same indicator compound that the group selected, namely, MMA (methylmalonic acid). MMA can build up in the bloodstream if there isn't enough vitamin B12 in the body.

The 25-microliter sample size needed for the new MMA assay represents a 4- to 10-fold reduction in the volume of specimen required for other MMA-based B12 tests. Samples take only about four minutes to process.