Serum methylmalonic acid in uraemia

The marker of cobalamin deficiency, plasma methylmalonic acid, correlates to plasma creatinine

“…It has been argued for years that the sensitivity of plasma cobalamins is low [1, 2] and it is well known that P‐MMA may be high in conditions not related to cobalamin deficiency. An increased P‐MMA is seen in renal insufficiency [14–16], thyroid disease, small bowel bacterial overgrowth, and conditions with haemoconcentration [25], but the frequency of non‐specific elevations in P‐MMA due to these reasons is unknown. As noted by Chanarin and Metz [12] the specificity of P‐MMA has not been adequately evaluated.…”

“…P‐MMA is elevated in patients with impaired kidney function, as expressed by elevated plasma creatinine [10, 14–16]. However, little is known about the association between P‐MMA and plasma creatinine in the whole range of values of plasma creatinine.…”

Review of cobalamin status and disorders of cobalamin metabolism in dogs

“…Careful interpretation of serum MMA concentrations should be exercised in the presence of other conditions that can affect serum MMA concentrations, such as renal insufficiency causing increased serum MMA concentrations . Therefore, serum concentrations of creatinine, symmetric dimethylarginine, or both should also be evaluated when interpreting serum MMA concentrations .…”

Dementia Associated With Vitamin B12 Deficiency

“…42,43 Serum HY levels were also found to be significantly higher, and serum folate and vitamin B 12 levels lower, in patients with senile dementia of Alzheimer type than in control subjects. 48 Certain anaerobic intestinal flora can cause MMA elevation due to the production of propionic acid, a precursor of MMA. 21 One possible explanation for vitamin B 12 deficiency with only borderline subnormal vitamin B 12 serum levels is the presence of cobalamin analogues that cause high vitamin B 12 values in presently used assays with R-binders.…”