Table 1.

Comparison of the original derivation cohort (Bendapudi et al) and current external validation cohort (Li et al)

	Derivation Cohort (n=214)	Validation Cohort (n=112)	P value
Demographic Features
Geographic Location	New England	Pacific Northwest
Age (years)	51 (38–63)	48 (34–58)	0.050
Female Sex	129/214 (60%)	71/112 (63%)	0.633
White Ethnicity	157/204 (77%)	72/106 (68%)	0.102
Clinical Data
Received FFP Prior to Testing	0/214 (0%)	27/112 (24%)	<0.001
Received Plasma Exchange	124/214 (58%)	58/112 (52%)	0.291
Recent Cancer Treatment	61/214 (29%)	28/112 (25%)	0.516
Previous Transplant	37/214 (17%)	22/112 (20%)	0.650
Laboratory Data
Reference Laboratory	BloodCenter of WI	BloodWorks NW
ADAMTS-13 Activity (%)	44 (0–63)	59 (33–82)	<0.001
Severe Deficiency †	62/214 (29%)	20/112 (18%)	0.032
Inhibitor Present ‡	52/214 (24%)	18/112 (16%)	0.090
Platelet Count (×10^9/L)	34 (18–59)	42 (19–71)	0.383
Creatinine (mg/dL)	1.7 (1.1–3.4)	2.0 (1.2–3.6)	0.312
Lactate Dehydrogenase (U/L)	963 (637–1594)	787 (450–1537)	0.032
International Normalized Ratio	1.1 (1.1–1.3)	1.3 (1.1–1.5)	<0.001
Bilirubin (mg/dL)	1.8 (1.0–3.1)	1.8 (1.0–2.9)	0.967
Completeness of Data
All Components of Score (%)	200/214 (93%)	108/112 (96%)	0.317

Continuous variables are expressed as median (IQR) and categorical variables are expressed as number/total (%). Continuous variables are compared using the rank sum test. Categorical variables are compared using the Fisher’s exact test.

^†Severe deficiency is defined as ADAMTS-13 ≤10% in the derivation study and ≤15% in the external validation study.

^‡A positive inhibitor is defined as a titer >0.4 Bethesda units.