Wednesday, October 28, 2015

CMHS Cycle 2 and Cycle 3 question


One of our co-investigators was told, about a year ago, that she could not bring the Cycle2 and Cycle3 data together in order to run comparisons. We were wondering if this had to do with methodological changes that happened between the 2 cycles – but have been unable to find any information to this effect. We are particularly interest in the Iron and Ferrin measures.


I consulted with the subject matter division and they provided the following response:

Ferritin is the only iron indicator that we study. Ferritin data
Ferritin data was obtained using an immunoassay on the Centraur XP in cycle 3 and on the Immulite 2000 in cycle 2. Results from these two different immunoassays can only be compared with caution and after applying a correction factor of 0.96319 to the cycle 2 data (i.e. adjusted cycle 3 ferritin = cycle 2 ferritin * 0.96319).

It is in the user guide for Cycle 3.