The reason we don't have calcitriol or 1,25 dihydroxy vitamin D in the software is that it is not a reliable indicator of vitamin D sufficiency.
1,25 dihydroxy vitamin D levels can fluctuate with calcium intake and are often normal even in cases of vitamin D deficiency. Dr. Alan Gaby's book "Nutritional Medicine" in the 2nd Edition confirms this, explaining that "the serum 1,25 dihydroxy vitamin D level is not a dependable marker of vitamin D status because vitamin D deficiency can lead to increased parathyroid hormone levels, which in turn raise 1,25 dihydroxy vitamin D levels." This information is supported by a study by Holick MF published in the American Journal of Clinical Nutrition in 2004.
According to Dr. Gaby, "the serum half-life of 25(OH)D is about 3 weeks, which makes it more useful as an indicator of long-term vitamin D status".
We recommend testing for 25(OH)D on your patients and adding the result into the ODX software will give you an indication of vitamin D status as well as historical changes in levels.
Reference
Source: Alan Gaby, "Nutritional Medicine" (2nd edition), page 114
Holick MF, "Vitamin D: Importance in the prevention of cancers, type 1 diabetes, heart disease, and Osteoporosis," Am J Clin Nutr 2004;79:362-371.