Table 2:

Number of cases identified via review of the medical record versus ICD-9 code search.

		Medical record data versus ICD-9 code search data
		Congruent		Incongruent
Diagnosis	Number of potential cases identified via initial ICD-9 code search	Present in both medical record and ICD-9 code search (True positives)	Absent in both medical record and ICD-9 code search (True negatives)	Present in medical record, absent in ICD-9 code search (False negatives)	Absent in medical record, present in ICD-9 code search (False positives)
Conjunctivitis (N = 1,695)	2,535	1,599	2,478	96	936
Congenital nasolacrimal duct obstruction (N = 1,275)	1,445	1,184	3,573	91	261
Pseudostrabismus (N = 173)	209	160	4,887	13	49
Retinopathy of prematurity (N = 76)	87	75	5,021	1	12
Esotropia (all subtypes) (N = 40)	89	31	5,011	9	58
Ptosis (N = 39)	31	24	5,063	15	7
Preseptal cellulitis (N = 33)	12	1	5,065	32	11
Exotropia (all subtypes) (N = 31)	24	15	5,069	16	9
Subconjunctival hemorrhage (N = 26)	27	21	5,077	5	6
Physiologic anisocoria (N = 23)	25	22	5,083	1	3

Abbreviations: N = number of cases confirmed via individual review of the medical record.