Data Methods

 Knowledge of HIV Status

Knowledge (or awareness) of HIV-positive status means a person is tested and diagnosed with HIV. Knowledge of HIV status is estimated as the percentage of persons with HIV who have received a diagnosis and is calculated by dividing the estimated number of persons living with diagnosed infections by the estimated total HIV prevalence (diagnosed and undiagnosed cases) for each year. Estimates derived by using HIV surveillance data and CD4 data for persons aged ≥13 years at diagnosis. 

For more specific information about how knowledge of status is calculated, please refer to the CDC’s HIV Surveillance Report: https://www.cdc.gov/hiv/pdf/library/reports/surveillance/cdc-hiv-surveillance-supplemental-report-vol-26-1.pdf

Estimates should be interpreted with caution for jurisdictions that do not have laws requiring complete reporting of laboratory data or has incomplete reporting. Areas without laws: Idaho and New Jersey. Areas with incomplete reporting: Kentucky, Pennsylvania (excluding Philadelphia), Puerto Rico, and Vermont.

Estimates should be interpreted with caution due to incomplete ascertainment of deaths that occurred during the year 2019. Areas with incomplete ascertainment of deaths: Kansas, Massachusetts, Mississippi, Nevada, North Dakota, and Vermont. 

Data for the year 2021 are preliminary. Due to the impact of the COVID-19 pandemic, data for the year 2020 should be interpreted with caution. COVID-19 disruptions in HIV, diagnosis, care and reporting of deaths during 2020 have also made incidence, prevalence, and knowledge of status estimates derived from a CD4-based model, unreliable. Therefore, the HIV surveillance supplemental report Estimated HIV Incidence and Prevalence in the U.S., which provides data on estimated incidence, prevalence, and knowledge of status in the U.S., was not published by CDC this year.

Relative Standard Error (RSE)

Relative standard errors (RSEs) were calculated for estimates of incidence, prevalence, and percentages of persons living with diagnosed HIV infection and were used to determine the reliability of estimates. Estimates with a RSE of < 30% meet the standard of reliability and is displayed. Estimates with a RSE of 30%–50% meet a lower standard of reliability and is displayed but should be interpreted with caution. Estimates with a RSE of > 50% are statistically unreliable and not displayed

Estimates with a relative standard error (RSE) of ≥30% do not meet the standard of reliability and are represented in the following way:

• Estimates with an RSE of 30% - 50% are marked with an asterisk (*), indicating that they should be used with caution.
• Estimates with an RSE>50 percent are not shown, and are replaced with the phrase “Data N/A due to high relative standard error.”

To reflect model uncertainty, all estimates were rounded to the nearest 100 for estimates of more than 1,000 and to the nearest 10 for estimates of less than 1,000.

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. 

Estimates of new HIV infections (HIV incidence) and knowledge of HIV status are not available for the year 2020 due to the impact of the COVID-19 pandemic on HIV testing. More time and data are needed to accurately assess COVID-19’s impact on HIV transmission in the United States.

For more specific information about how Knowledge of HIV Status is calculated, refer to:  HIV Surveillance Supplemental Report 2015-2019, Volume 26, No. 1.

More information about Knowledge of HIV Status data can be found at: HIV Surveillance Report 2020, Volume 33.

The most recent CDC Knowledge of HIV Status data can be found at: HIV Surveillance Data Tables 2022, Vol. 3, No. 1.