Data Methods
Learn more about the data that informs AHEAD.
Data Methods
Linkage to HIV Medical Care
Linkage to HIV medical care was measured by documentation of ≥1 CD4 or VL tests ≤1 month after HIV diagnosis. Of note, this indicator is only available for states that have complete data. These states have reported at least 95% of laboratory results to their surveillance programs and have transmitted their data to CDC’s National HIV Surveillance System (NHSS). NHSS includes data for persons aged ≥13 years. Linkage to care data by jurisdiction are based on residence at time of diagnosis of HIV infection.
For the baseline year 2017, linkage to HIV medical care was available for 41 states and the 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.
For 2019, 2020, and 2021, the number of jurisdictions with complete laboratory data increased to 45. Linkage to HIV medical care data is available for 44 states and the District of Columbia including: Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Illinois, Indiana, Iowa, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, 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.

Linkage to care data are not provided for jurisdictions that do not have laws requiring reporting of all CD4 and viral loads, or that have incomplete reporting of laboratory data to CDC. Areas without laws: Idaho and New Jersey. Areas with incomplete reporting: Kentucky, Pennsylvania (excluding Philadelphia), Vermont, and Puerto Rico.
Totals for linkage to care include other risk factors, such as persons whose infection was attributed to hemophilia, blood transfusion, or perinatal exposure or whose risk factor was not reported or not identified. These data are not displayed in tables because the numbers are too small to be meaningful.
Data presented by quarter: Linkage to care for a quarter is calculated for the cumulative number of persons who received an HIV diagnosis through the specified quarter of the 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 December 2021 is calculated using data reported to CDC’s National HIV Surveillance System through March 2022). Data presented by quarter are preliminary.
Data for the year 2020 should be interpreted with caution due to the impact of the COVID-19 pandemic on access to HIV testing, care-related services, and HIV case surveillance activities in state/local jurisdictions. Inclusion of 2020 data in trend assessments is discouraged.
Data for the year 2021 are considered preliminary and based on data reported to CDC’s National HIV Surveillance System as of March 2022. Linkage to HIV Medical Care data are preliminary through December 2021.
Data reported to the NHSS are considered preliminary until a 12-month reporting delay has been reached.
More information about Linkage to HIV Medical Care data can be found at: HIV Surveillance Report Supplemental Report Volume 27, Number 3.
The most recent CDC Linkage to HIV Medical Care data can be found at: HIV Surveillance Data Tables 2022, Vol. 3, No. 2.