Hello lauren8844
The methylmalonic acid test is a more sensitive test for vitamin B12 deficiency. It is used as a follow up test for those that have low or low normal levels of B12, particularly if they have symptoms, such as those patients with PN.
B12 is a water soluble vitamin secreted by the kidneys. It does not "stay" or accumulate in the blood. This is even true of people who have B12 absorption problems.
The folate test has nothing to do with the B12 test or problems with B12 absorption.. It tests for the level of another B vitamin, folic acid.
I'd be curious to find out if @nukhan is taking supplements, particularly B12. If so, that would explain the high B12 level on the test.
The proper order would be a screening B12 test, then, if indicated, a methylmalonic acid and homocysteine test. If the last 2 are abnormal, a problem with B12 absorption is present. There are many causes of this condition, including old age.