In the case of labwork, the old adage definitely applies: the devil is in the detail. Markers supposedly measuring the same substance or dynamic in the body can be dramatically different (and accurate or not!) based on the form in which they are assessed. Check out this clinical tip video to learn more about cellular markers. In particular, I want you to be savvy about methylmalonic acid (MMA) as a cellular marker for Vitamin B12 sufficiency.
I have written before about the critical importance of Vitamin B12 and how you can learn to spot insufficiency in your clients. An important skill because insufficient Vitamin B12 can have dramatic (and perhaps unexpected) consequences: Here’s one client who was definitely wildly satisfied about discovering this deficiency in her body. MMA should optimally be in the lower half of the typical reference range.
If you’d like a geek dive into Vitamin B12 and MMA and its function in the body, please check this out. MMA is also included in a number of clinical studies looking to assess B12 sufficiency (e.g. this one on polyneuropathy and this one citing the prevalence of insufficient B12 in people who have undergone gastric surgery). Urinary MMA is likely to be more accurate because renal (kidney) issues can cause serum MMA to be elevated (though mildly), but both serum and urinary markers are valuable.
If you have any follow-up questions, please feel free to post below. I am happy to help you!