Chlamydia Profiles, 2010
This web page is archived for historical purposes and is no longer being updated. Newer data is available on the STD Data and Statistics page.
• Figure A Data, All Regions - Chlamydia - Trends in positivity in 15 to 24 year old women tested in family planning clinics
Each of the Regional Profiles, one for each of the ten HHS regions, contains a map of the region and a bar graph showing trends in chlamydia positivity rates among women 15 to 24 years of age attending family planning clinics. Information on the proportion of all chlamydia tests performed that were nucleic acid amplification tests (NAATs) is included. NAATs are the most sensitive tests currently available for the detection of genital Chlamydia trachomatis infections and may be performed on a variety of biologic specimens. NAAT usage has been increasing over time in each of the ten HHS regions. For more information on NAAT usage in this population, see Figure 13 of STD Surveillance, 2010. For more information on prevalence monitoring data, see below.
• Figure A Data, All States - Chlamydia rate per 100,000 women, 2000 - 2010
• Figure B Data, All States - Chlamydia positivity in women 15 to 24 years of age, by testing site, 2000 - 2010
• Figure C Data, All States - Chlamydia positivity by age group in women attending family planning clinics, 2010
• Table 1 Data, All States - Chlamydia positivity in women 15 to 24 years of age, by testing site, 2010
Each of the State Profiles on chlamydia positivity trends contains three figures and one table.
Morbidity Surveillance: Reporting of Chlamydia Cases
Crude case rates (reported cases/population) were calculated on an annual basis per 100,000 population. Rates for all states were calculated by dividing the number of cases reported from each state by the estimated state-specific population (the most current detailed population file available at time of publication).
From 2001 to 2002, population estimates for Puerto Rico were obtained from the Bureau of Census, and estimates for the Virgin Islands were obtained from the University of the Virgin Islands. After 2002, population estimates for all outlying areas were obtained from the Bureau of Census website.
Due to use of updated population data, rates presented in the current State Profiles may be different from prior State Profiles.
Prevalence Monitoring: Reporting of Chlamydia Positivity
Chlamydia test positivity was calculated by dividing the number of women testing positive for chlamydia (numerator) by the total number of women tested for chlamydia (denominator includes those with valid test results only and excludes unsatisfactory and indeterminate tests) and is expressed as a percentage. The denominator may contain multiple tests from the same individual if that person was tested more than once during the period for which screening data are reported. The numerator may also contain multiple positive test results from the same individual if that person tested positive more than once during the period for which screening data are reported. Various chlamydia laboratory methods were used and no adjustments of test positivity were made based on laboratory test type and sensitivity.
The number of clinics cited in Table 1 for each state represents family planning (FP), sexually transmitted disease (STD), prenatal, and other clinics screening 25 or more women and juvenile and adult corrections facilities screening 100 or more women. To be included in Figure B, FP and STD clinics must have each had data on at least 50 tests in any given year and the National Job Training Program must have had data on 100 or more entrants in any given year. Each age group displayed in Figure C represents data on at least 100 tests within the past year.
City Profiles have been discontinued. Local areas are encouraged to create their own profiles to best reflect their geographic area and available data. Data on chlamydia cases and rates at the MSA are in the current STD surveillance report.
Regional Infertility Prevention Projects
Chlamydia screening and prevalence monitoring activities were initiated in Health and Human Services (HHS) Region X in 1988 as a CDC-supported demonstration project. In 1993, as part of the development of the National Infertility Prevention Program (IPP), chlamydia screening services for women were initiated in three additional HHS regions (III, VII, VIII); in 1995, services were implemented in the remaining HHS regions (I, II, IV, V, VI, IX). All regional projects, in collaboration with state STD control and family planning programs, have reported chlamydia positivity data to CDC since 1997. In some of the HHS regions, federally-funded chlamydia screening supplements existing local-and state-funded testing programs. These publicly-funded programs support chlamydia screening primarily in family planning clinics, but also in some STD clinics, prenatal clinics, jails and juvenile detention centers, and other sites.
The 10 HHS regions referred to in the text and figures are as follows:
- Region I: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, Vermont
- Region II: New Jersey, New York, Puerto Rico, and U.S. Virgin Islands
- Region III: Delaware, District of Columbia, Maryland, Pennsylvania, Virginia, West Virginia
- Region IV: Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, Tennessee
- Region V: Illinois, Indiana, Michigan, Minnesota, Ohio, Wisconsin
- Region VI: Arkansas, Louisiana, New Mexico, Oklahoma, Texas
- Region VII: Iowa, Kansas, Missouri, Nebraska
- Region VIII: Colorado, Montana, North Dakota, South Dakota, Utah, Wyoming
- Region IX: Arizona, California, Hawaii, Nevada
- Region X: Alaska, Idaho, Oregon, Washington
State and Local Health Departments
As of 2000, all 50 states and the District of Columbia had regulations requiring the reporting of chlamydia cases.
Corrections data are reported as part of the Regional Infertility Prevention Projects.
National Job Training Program
The National Job Training Program is primarily a residential job training program for urban and rural economically-disadvantaged youth 16 to 24 years of age at more than 100 sites throughout the country. Since 1990, approximately 20,000 female National Job Training Program entrants have been screened each year for chlamydia, with all tests performed at a central contract laboratory. Changes in the test type used for females occurred in 1998, switching from the EIA to the DNA hybridization probe (GenProbe PACE 2). Beginning in 2000, a small proportion of females were screened using the strand displacement assay (BDProbeTec ET). By 2006, most females were screened using the strand displacement assay. Since July 2003, male National Job Training Program entrants have also been screened for chlamydia using the strand displacement assay. Annually, over 35,000 men are screened. The chlamydia test results from the National Job Training Program were used to calculate prevalence in this population.
The interpretation of chlamydia data is complicated by several factors. First, as chlamydia is usually asymptomatic, case report data are influenced by screening coverage. Second, both case report and positivity data result from the use of several different types of diagnostic tests for chlamydial infection (e.g., direct fluorescent antibody, EIA, DNA probe assay, nucleic acid amplification); these tests vary in their sensitivity and specificity. Nucleic acid amplification tests (NAATs) are the most sensitive tests currently available in the United States. Third, chlamydia positivity in women attending clinics is an estimate of prevalence; it is not true prevalence. Crude positivity may include those women who are tested two or more times during a single year. Comparisons of positivity with prevalence have shown that in family planning clinics, positivity is generally similar to or slightly higher than prevalence, and in STD clinics, positivity is somewhat lower than prevalence; however, these differences are usually small, with a relative difference of less than 10% (Dicker et al., 1998). Additionally, while nearly all family planning clinics perform universal screening of sexually active women < 20 years of age, and most clinics do so among women < 26 years of age, some selective screening is performed among women 20-to 25-years of age and selective screening is frequently performed among women > 26 years of age. Fourth, family planning and other clinic-based data reported to CDC may not be fully representative of the entire clinic population. Reporting completeness requirements and programmatic influences may lead to only partial reporting from some clinics. Additionally, clinics participating in IPP may change over time. Consequently, data trends should be interpreted with caution. Finally, while monitoring prevalence among persons seeking care at clinics provides important information on certain segments of the population, these data cannot be generalized to the population as a whole.
In the National Job Training Program (NJTP), data are limited to entrance exam testing; therefore, no one is included twice and true prevalence is ascertained as all persons entering the NJTP are required to be tested. However, these data cannot be generalized to the population not entering the NJTP.
As noted above, various laboratory test methods were used for all data. The figures presented in this report do not include an adjustment of test positivity based on laboratory test type and sensitivity.
- Page last reviewed: March 29, 2012 (archived document)
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