Table 3.

The Validity of Various Algorithms for Identifying Cases of Acute Ischemic Stroke

Algorithm	TP	FP	FN	PPV (95% CI), %	Sensitivity (95% CI), %
I63* as primary diagnosis	1124	2	165	99.8 (99.4–100)	87.2 (85.3–89.0)
I63* as primary or first secondary diagnosis	1201	20	88	98.4 (97.5–99.0)	93.2 (91.7–94.5)
I63* as primary, first secondary, or second secondary diagnosis	1255	37	34	97.1 (96.1–98.0)	97.4 (96.3–98.2)
I63* in any position of diagnosis	1281	101	8	92.7 (91.2–94.0)	99.4 (98.8–99.7)

Note: I63* means all the diagnosis codes that begin with I63.

Abbreviations: CI, confidence interval; FN, false negative; FP, false positive; PPV, positive predictive value; TP, true positive.