TABLE II.

Clinical Course of Piperacillin-Induced Thrombocytopenia in 12 Patients

Patient	Baseline platelet count (×10−3/µL)	Days receiving piperacillin before thrombocytopenia	Nadir platelet count (×10−3/µL)	Days to normal platelet count after piperacillin discontinued
1	250	1	2	4
2	212	6	14	5
3	237	7	18	5
4	310	6	10	14
5	250	7	5	>6a
6	332	9	25	3
7	Normal	7	3	5
8	820	10	20	4
9	238	6	17	5
10	255	5	10	7
11	215	1	40	>7a
12 (1st)	353	5	33	5
12 (2nd)	377	1	14	3
Median valuesb	250	6	15.5	5

Clinical data are available on 11 of 13 patients in whom piperacillin-dependent platelet-reactive antibodies were documented at the BloodCenter of Wisconsin. Patient 12 is the patient presented in this report.

^aDaily platelet counts were not recorded until platelet ≥150,000/µL.

^bMedian values for the 11 patients from the BloodCenter of Wisconsin and the first episode of thrombocytopenia for our patient.