Cases

COVID-19 Cases and Deaths

How are cases and deaths counted in NC?

A “COVID-19 case” is a person who received a positive COVID-19 test result.  People are only counted as a case once, even if they have multiple positive tests.

Starting September 25, 2020, the North Carolina Department of Health and Human Services (NCDHHS) began reporting on two new measures on the NC COVID-19 Dashboard: 1. Antigen-positive cases and deaths, and 2. Antigen tests completed. This change was made in accordance with recently updated case classification guidelines from the Centers for Disease Control and Prevention.

Both molecular (PCR) and antigen tests are diagnostic. This means that they look to see if someone is currently infected with COVID-19. Each test looks for different things to determine if someone is infected.

  • A molecular (PCR) test looks for the virus’s genetic material.
  • An antigen test is a rapid test that looks for specific proteins on the surface of the virus.

Where the test is processed may also differ.

  • Molecular (PCR) tests are processed in a laboratory.
  • Antigen tests are often processed at the point of care, such as in a health care provider’s office.

A molecular (PCR) positive case of COVID-19 is a person who received a positive COVID-19 result from a molecular (PCR) test. An antigen positive case of COVID-19 is a person who received a positive COVID-19 result from an antigen test and does not have a positive result from a molecular (PCR) test. 

Molecular (PCR) positive cases are classified as “confirmed” cases and antigen positive cases are classified as “probable” cases of COVID-19, in accordance with CDC case classification guidelines. Despite the names, regardless of the test used, a person who tests positive is considered to have COVID-19. The terms “confirmed” and “probable” are used nationally to standardize case classifications for public health surveillance but should not be used to interpret the utility or validity of any laboratory test type.

For more information about different types of COVID-19 tests, visit the Food and Drug Administration’s overview of coronavirus testing basics.

Data on cases and deaths, including number, demographics, county and ZIP code of residence, come from the North Carolina COVID-19 Surveillance System (NC COVID). Data on cases and deaths include both molecular (PCR) and antigen positive cases. County and ZIP code case and death totals may not match the total NC cases or deaths; this could be attributed to incomplete information.

Because reporting COVID-19 is mandatory in North Carolina, clinicians and laboratories must report results of all COVID-19 molecular (PCR) and antigen tests to local or state public health. Some laboratories report COVID-19 test results into NC COVID through electronic laboratory reporting. These test results automatically feed into NC COVID and populate the system with any available information on the laboratory report about the person. However, not all laboratories currently report electronically. Test results from clinicians or laboratories that don’t have electronic reporting are reported to local or state public health via secure fax or electronic files. Positive test results are manually entered into NC COVID by NCDHHS or Local Health Department (LHD) staff.

COVID-19 deaths include people who have had a positive molecular (PCR) or antigen test for COVID-19, who died without fully recovering from COVID-19, and who had no alternative cause of death identified. Deaths are reported by hospitals and clinicians directly to the local and state health departments. Once reported, NCDHHS or LHD staff manually enter the death by date of death, into NC COVID.

NCDHHS conducts ongoing data quality checks on NC COVID data, including ensuring that there are no duplicate cases, and removing cases that are not NC residents, consistent with national guidance. After conducting data quality checks, the data are used to calculate the COVID-19 metrics posted on the NCDHHS website.

Cases by date reported shows the number of new cases on the report date compared to the previous day. These are displayed with a 7-day rolling average as a trendline. Cases include both molecular (PCR) positive and antigen positive cases.

Cases by date of specimen collection show molecular (PCR) positive and antigen positive cases by the date the person was tested. This method is what is often used to track other communicable diseases. As new cases are reported, they are added to the date that the test specimen was collected, and so the number for previous days can change. There is typically time between when the person is tested, the test is run at a lab, and the test result is reported to the state or LHD. Because of this, the data for the most recent days are considered preliminary and incomplete, which is represented by the grey box in the graph. 

Deaths by date of death show deaths on the date the person died. Deaths are typically reported within hours or days. As new deaths are reported, they are included in the date the person died, and so previous dates can change. Deaths include those among molecular (PCR) and antigen positive cases.