Hi James V,
I tracked HGB vs HCT. My HGB increased rather rapidly after ATG and then fell. It took 8 months for me to slowly reach that post HGB level. If I look at my HCT, it bumped around until about the 6 month mark and then started a slow steady rise.
It is important to look for trends over the period of maybe 3 months. Try not to read too much into a single reading. Hydration levels, viruses, or lab inaccuracies are just a few variables that may affect a single result.
With regards to reticulocyte percentage, my doctor didn't check this often. When he did (after 3 months), it was usually in the 1.5 - 2.3% mark. When I was sick, it would be lower.
You could hypothesize that when your wife's reticulocyte count was high, it may have been because there was an intense immune attack going on that was rapidly destroying the RBCs. So the marrow was trying to keep up by cranking out the baby red cells. Post-ATG, you could argue that the major immune attack has been thwarted. Now the marrow still must slowly heal and rebuild. So retic count has normalized again.
Hope that helps! Try not to panic (always easier to say retrospectively)! You will learn patience with this disease
