What does it mean if both my b12 & folates (folic acid) are low in one blood test but just b12 in repeat blood test?

There is a degree of: variability in any statistical test. Most blood tests are simply a snapshot of where your levels are a the time the blood was drawn. A more sensitive test is the Micronutrient test from Spectracell Lab in Texas. It measures more than 30 micronutrients, including the B vitamins and tells you how your body absorbs them. Peace and good health.

Food supplements: Folate is added to many foods, e.g. cereals. If your folate level was marginally at the first reading, it may have been corrected though normal food intake. B12 absorption is more complex and may need injections to supplement. With the exception of B12 and vitamin D you do not need supplements if you are eating a mixed diet. And testing for "micronutrients" is a waste of money.