Background:
Gonorrhea (GC) is the second most commonly reported notifiable disease in the US. Although state law requires mandatory reporting of gonorrhea by both providers and laboratories, underreporting of cases and incomplete case reports are common. Estimating these parameters of case reports is needed to better understand the demographic distribution of GC cases so that interventions can be more effectively directed. Additionally, physician reports contain treatment and other information not available in laboratory reports.

Objective:
The objective of this evaluation was to estimate the number of unreported GC cases and incomplete case reports.

Method:
GC data from 2004 were categorized by source of reports and underreporting was estimated by the capture-recapture method.

Result:
In 2004, a 2,376 GC cases were reported from the following sources: 35% from laboratories only, 15% from physicians only, and 49% from both. From the capture-recapture method, an additional estimated 253 cases were identified as not being reported (9% underreporting rate). Only 71% of zip codes and 38% of race/ethnicity data were reported. Compared with laboratory reports, provider reports had a higher rate of race/ethnicity completeness (54% versus 6%, rate ratio [RR]=9.2, 95% confidence interval [CI]=8.6-10.2, p = <0.001, and more often contained patient zip codes (83% versus 51%, RR=1.7, CI=1.5, 1.8, p= < 0.001). Race/ethnicity data from Sexually Transmitted Disease (STD) clinics were more complete than reports from other clinics, (58% versus 38%, RR=1.8, 95% CI =1.7, 2.0, p=<0.001). However, STD clinic reports comprised only 23% of total GC reports.

Conclusion:
GC case reports are often incomplete and might provide a biased estimate of race/ethnicity and zip code distribution. Efforts to increase physician reporting might improve completeness.

Implications:
Surveying physicians to identify barriers to reporting and conducting periodic random sampling of GC cases to estimate demographic, treatment and risk factors should be considered as an alternative approach.