Table 3 : Medical record validation of pure red cell aplasia (PRCA) cases
identified by claims-based algorithms.

Total	Possible PRCA	Probable PRCA
	17	15
Number of true positives*	0	0
Number of false positives†	17	15
Positive predictive value (PPV; 95% CI)‡	0.0 (0.0-19.5)	0.0 (0.0-21.8)

CI: Confidence interval; PPV: Positive predictive value; PRCA: Pure red cell aplasia
^*Evidence of PRCA identified from claims data using the preliminary claims-based
algorithm and confirmed from medical record review.
^†Evidence of PRCA identified from claims data using the preliminary claims-based
algorithm but not confirmed from medical record review.
^‡Positive predictive value (PPV) is defined as the number of true positives divided by
the sum of the number of true positives and the number of false positives. 95% CIs
are exact binomial CIs.