Table 1.

Characteristics of the donors

Characteristic	1 or 2 Sessions group (n = 20)	3 to 19 Sessions group (n = 20)	20 to 24 Sessions group (n = 20)	P
Age, year, median (range)	37.5 (19-72)	60.5 (21-76)	62.5 (28-79)	.003
Sex, n (%)				.096
Female	10 (50)	5 (25)	4 (20)
Male	10 (50)	15 (75)	16 (80)
Race, n (%)*				.105†
White	14 (70)	18 (90)	19 (95)
Other	3 (15)	1 (5)	0 (0)
Not reported	3 (15)	1 (5)	1 (5)
Plateletpheresis sessions, n (range)
Median in prior 365 d	1 (1-2)	9 (3-19)	23 (20-24)
Median in prior 20 y	2 (1-76)	95 (3-322)	256.5 (21-461)	<.001

^*Race was reported by the donor. “Other” includes Asian, black or African American, and more than 1 race.

^†The P value does not take into account the “Not reported” category.