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X Fact
February 27, 2021
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Why Doctors Should be Ordering uMMA Tests for B12 Deficiency

In the last X Fact Is There a Better Blood Test for B12 Deficiency Other Than a B12 Level, it was explained how MMA will accumulate in the cell when there is not enough B12 to meet its energy needs and can be measured in blood as an indicator of B12 deficiency. But, the MMA level in blood is rapidly filtered through the kidneys and concentrated in the urine up to 40 times as much as in the blood and therefore, even slight elevations above normal can be more easily detected. This concentration effect and the fact that MMA is much more stable in urine than blood (up to three weeks in a urine sample at room temperature) makes it a much more reliable and sensitive test than measuring blood MMA.

One more point. Because kidney filtration can vary from one time to another within the same individual, or between people with different levels of kidney function, the amount of MMA measured in urine always has to be compared to creatinine (a waste product) measured in the same sample. Because creatinine is a reliable indicator of kidney function and filtration, the MMA/creatinine ratio can correct for any decrease in kidney function or high filtration rates, that can give falsely elevated results. This is why the test is reported as micrograms MMA per milligrams creatinine (mcg MMA/mg creatinine) and a value above 3.8mcg MMA/mg creatinine indicates vitamin B12 deficiency and a value below 3.8 indicates adequate cellular B12 status. Simple as that.

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A creatinine test is a measure of how well your kidneys are performing their job of filtering waste from your blood. Creatinine is a chemical compound left over from energy-producing processes in your muscles. Healthy kidneys filter creatinine out of the blood. Creatinine exits your body as a waste product in urine. A measurement of creatinine in your blood or urine provides clues to help your doctor determine how well the kidneys are working.

Who Wrote This X Fact
Jonathan Bortz MD
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Jonathan’s background as a practicing diabetes specialist for 15 years and 17-year career developing nutritional prescriptive products for the pharmaceutical industry has contributed to his ability to understand nutrients, how they work and why they are important.

Over the years he has acquired broad and in-depth knowledge in minerals, essential fatty acids and other nutrients, but has special expertise in Vitamin B12 and choline metabolism. He is often asked to speak at national and international venues to articulate why B12, folate and choline are so important to gene function, brain development, liver and cardiovascular health. He applies pharmaceutical standards to nutrient science and has developed a unique ability to translate complicated concepts into simple promotional messages that resonate with practitioners and consumers. He has developed dozens of innovative nutritional products, of which many are category leaders in the US. Jonathan obtained his medical degree from the University of the Witwatersrand Medical School in South Africa and did his fellowship in Endocrinology at Washington University in St. Louis, MO.

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