> Was it just the delay in solids or could a
>recent illness and course of antibiotics have any corelation at all?

One of the body's adaptive responses when infected by a bacteria or virus,
is to hoard iron, keeping it in the cells and out of the bloodstream.  That
way, the infectious agents have a hard time reproducing, because they need
iron, too.  If the child recently had an illness, then he probably has
plenty of iron in his body, but it isn't in his bloodstream to be measured.

Iron-hoarding, like generating a fever, are the body's adaptive responses to
infections.
Katherine A. Dettwyler, Ph.D.
Associate Professor of Anthropology and Nutrition
Texas A&M University