From "Outpatient Diagnostic Errors: Unrecognized Hyperglycemia" Effective Clinical Practice, January/February 2002. 5:11-16.
Figure 2. Accuracy of ICD-9 coding. Of the 1384 patients with an ICD-9 code for diabetes, all but 80 (6%) had the diagnosis confirmed on the basis of laboratory data or chart review. FPG = fasting plasma glucose; HbA1c = hemoglobin A1c.>