Reticulated platelets predict platelet count recovery following chemotherapy
Article first published online: 21 APR 2002
Volume 42, Issue 3, pages 368–374, March 2002
How to Cite
Wang, C., Smith, Brian R., Ault, Kenneth A. and Rinder, Henry M. (2002), Reticulated platelets predict platelet count recovery following chemotherapy. Transfusion, 42: 368–374. doi: 10.1046/j.1537-2995.2002.00040.x
CIT = chemotherapy-induced thrombocytopenia; RP = reticulated platelet; RP-MI = reticulated platelet maturation index.
Supported by grants from the NIH (HL47193 and HL61223) and the American Heart Association.
- Issue published online: 21 APR 2002
- Article first published online: 21 APR 2002
- Received for publication July 13, 2001; revision received October 22, 2001, and accepted October 23, 2001.
BACKGROUND: A laboratory measure that predicted the timing of platelet recovery after chemotherapy could guide prophylactic platelet transfusion. Reticulated platelets (RPs) are the youngest circulating platelets; an increased percentage of RPs is diagnostic of increased marrow platelet production, such as seen with idiopathic thrombocytopenic purpura, whereas a low percentage of RPs with thrombocytopenia indicates marrow suppression. This study examined whether the percentage of RPs, in combination with a newly devised measurement of "stress thrombopoiesis," the RP maturation index (RP-MI), could predict platelet count recovery following chemotherapy-induced thrombocytopenia.
STUDY DESIGN AND METHODS: Platelet count nadirs were retrospectively determined in 35 chemotherapy-induced thrombocytopenia patients; percentage of RPs and RP-MI values were assayed at the early nadir (no imminent platelet recovery) and the late nadir (imminent platelet recovery). The latter was defined by a platelet count increase of 20 × 109 per L or more in the subsequent 48 hours without platelet transfusion.
RESULTS: Early in the nadir (when platelet recovery did not occur in the subsequent 48 h after sampling), a low RP-MI and a low percentage of RPs were found in 29 of 35 patients. Late in the nadir, when recovery was imminent, 27 of 30 evaluable patients had elevated percentages of RPs or RP-MI values; the mean time from sampling to an increase of 20 × 109 per L or more was 42 hours. The positive and negative predictive values of this assay were 82 and 91 percent, respectively. Furthermore, when thrombocytopenia was severe (platelet count ≤20 × 109/L), an elevated RP-MI and/or percentage of RPs correctly predicted imminent platelet count recovery in five of five patients.
CONCLUSION: This noninvasive, rapid, whole-blood assay of stress thrombopoiesis provides reproducible indices for timing platelet recovery following chemotherapy and the potential to optimize the use of prophylactic platelet transfusions in chemotherapy patients.