Figure.

Temporal trends for selected population characteristics by race/ethnicity among female clients aged 15–24 years tested for chlamydia in U.S. Public Health Service Region X family planning clinics, 1997–2006

^aEach annual data point is calculated as the weighted sum (based on proportion of each test type) of test-specific adjusted positivities. Test-specific adjusted positivity = (test-specific observed positivity + test specificity − 1) divided by (test sensitivity + test specificity − 1).