Data Methods

Learn more about the data that informs AHEAD.

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Linkage to HIV medical care indicator icon Linkage to HIV medical care

The linkage to HIV medical care indicator is measured by documentation of at least 1 CD4 or viral load test performed ≤1 month after diagnosis among persons aged ≥13 years. This indicator is only available for states with complete laboratory data (at least 95% of laboratory results are reported to the surveillance programs and transmitted to CDC). For the baseline year 2017, linkage to HIV medical care was available for 41 states and Washington, District of Columbia: Alabama, Alaska, California, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Illinois, Indiana, Iowa, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, New Hampshire, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, Washington, West Virginia, Wisconsin, and Wyoming. There are 41 areas with complete lab reporting for 2018 however, the composition of the states changed. In 2018, linkage was available for Nevada but not available for Connecticut. In 2019, the number of jurisdictions with complete laboratory data increased to 45.

Formula for the Linkage to Care indicator


  • EHE areas without laws requiring complete reporting:
    • Idaho
    • New Jersey
  • EHE areas with incomplete reporting:
    • Arizona
    • Arkansas
    • Connecticut (for 2018 only)
    • Kansas
    • Kentucky
    • Pennsylvania (excluding Philadelphia)
    • Vermont
    • Puerto Rico

Linkage to Care Map, 2017Linkage to Care Map, 2018Linkage to Care Map, 2019

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Linkage to HIV medical care data by quarter will be calculated for the cumulative number of persons who received an HIV diagnosis by the quarter of interest for the specified calendar year. A 3-month reporting lag is required for calculating linkage to care due to known delays in reporting of laboratory data (e.g., linkage to care through September 2020 is calculated using data reported to CDC’s National HIV Surveillance System through December 2020). Data presented by quarter are preliminary.

More information can be found at: HIV Surveillance Report Supplemental Report Volume 26, Number 2.