I thought that the white blood count (WBC) was the important number we were following. Turns out that the doctors are waiting on a sub-set of WBC called the absolute neutrophil count (ANC). Talitha's WBC is at 900 today but her ANC is only at 100. It's the ANC that needs to climb to 1,000 or more before they will resume chemo with cycle #2.
Wikipedia explains that "absolute neutrophil count (ANC) is a measure of the number of neutrophil granulocytes present in the blood. Neutrophils are a type of white blood cell that fights against infection.
"A normal ANC is above 1,500 cells per microliter. An ANC less than 500...is defined as neutropenia and significantly increases the risk of infection [Talitha is at 100]. Neutropenia is the condition of a low ANC, and the most common condition where an ANC would be measured is in the setting of chemotherapy for cancer."
So by definition, Talitha has sever neutropenia right now (i.e. ANC below 500). Mild neutropenia exists between 500 and 1,000. Once the ANC hits 1,000 or above, the risk of infection is considered low and chemotherapy can re-commence.
The daily neupogen shots will continue through at least Wednesday at which point we will hold off temorarily pending the blood draw results on Thursday. (There must be a minimum of 48 hours between the last neupogen shot and when chemotherapy is administered.) If Thursday's reading shows an ANC of at least 1,000, then Talitha will likely be admitted to the PCMC on Friday to start round 2.
Once again I'm reminded of the old saying, "It's what you learn after you think you know it all that really counts."