Question: When reporting engraftment dates, how do we use lab results to calculate ANC recovery?
To demonstrate engraftment for allogeneic recipients, particularly non-myeloablative or reduced intensity approaches, chimerism tests must be done. These measure the quantity of donor cells relative to the quantity of host (recipient) cells. While ANC usually represents donor cells in allogeneic HSCT, it cannot be proven without chimerism studies.
ANC recovery is defined as an absolute neutrophil count (ANC) of ≥ 0.5 x 109/L (500/mm3) for three consecutive laboratory values obtained on different days.* Date of ANC recovery is the date of the first of three consecutive laboratory values where the ANC is ≥ 0.5 x 109/L. At some institutions, the laboratory reports display the ANC value once there are sufficient white blood cells to perform a differential count. At other institutions, the laboratory reports do not display the ANC, and it must be calculated from the white blood cell count (WBC) and the percent of segmented and band neutrophils (if the differential was performed on a machine, the percent neutrophils will include both segmented and band neutrophils). If the laboratory report displays an automated ANC value of exactly 0.5, the actual ANC value should be calculated from the manual differential if available. The calculated value from the manual differential will determine ANC recovery. If your institution's laboratory reports do not display the ANC value, use the following calculation to determine the ANC:
Calculating Absolute Neutrophil Count (ANC)
Source: CIBMTR Forms Manual: Post-TED (Form2450), pages 6&7. For more information Click here.