Table 2.

Relationship between ICD-9-CM code documentation and laboratory serum sodium < 136 mmol/L

		Hyponatremia
		+	-
ICD-9 = 276.1	+	1407	839
	-	39,261	1,859,747

Sensitivity = 3.46%

Specificity = 99.95%

Positive predictive value = 62.64%

Negative predictive value = 97.93%