All following data are theoretical and not real:
A patient had a hemolytic crisis without anemia proven by elevated reticulocytes, elevated unconjugated bilirubin and normal hemoglobin and erythrocyte count. A week after taking the first test the patient took a second test - both unconjugated bilirubin and reticulocytes were twice lower than before (reticulocytes were within normal range this time, unconjugated bilirubin was still mildly elevated). Immature reticulocyte fraction was normal the first time and very low the second time. Is this a normal occurence or does it point to an aplastic crisis? All articles I found on this subject stated that low reticulocyte production is a sign of an aplastic crisis but I couldn't find any examples of patients with low IRF who are recovering from an acute hemolytic crisis.
MY EXPLANATION (very possibly incorrect):
Red blood cells were breaking down too quickly and they were compensated by elevated reticulocytes. When hemolysis (suddenly) stopped there were still a lot of reticulocytes swarming around the blood and maturing in the bone marrow which meant that the production had to be severely cut down in order to not produce too many reticulocytes and consequently too many red blood cells. So the immature reticulocyte fraction was very low because the body slowed down the production of new reticulocytes but there were still many old ones which created a very low ratio between the two groups. If this is true, bone marrow should start producing reticulocytes normally again very soon after the second test and IRF should be normal another week later.
MY CRITIQUE OF MY EXPLANATION (very possibly incorrect as well):
My explanation includes a premise that hemolysis stopped suddenly and not gradually which I find quite odd.