|COVID-19 Testing: A Review of the Basics|
|By By Brent Gibson, MD, MPH, CAE, CCHP-P, Chief Health Officer, National Commission on Correctional Health Care and managing director, NCCHC Resources, Inc.|
As the nation begins to get back to work and many patients recover from COVID-19, there is a lot of discussion, and a bit of confusion, about testing. People are putting a lot of faith in testing, and for good reason. Many of us would like a quick way to make risk assessment about our patients and populations and we are hopeful that testing for COVID-19 will do just that. In the clinical murkiness of COVID-19, the test for the virus that causes COVID-19 is important in correctional settings and everywhere. But many of the questions we receive here in our office suggest that people are looking to the test to screen asymptomatic patients and using the results as a litmus test for how to house and care for inmates. The issue is more complex than that, however.
My goal with this article is to explain the different types of tests available as well as their benefits and limitations, and provide some ideas and resources to help you make sound decisions.
Testing vs. Screening
Testing refers to a study or studies performed to detect the presence or absence of a specific disease or condition, like COVID-19.
Screening, on the other hand, can detect indicators of a potential disease that warrants confirmation (often through a test). Diagnostic studies (e.g., radiography, laboratory work) may be a part of screening; a series of questions or other types of inquiry is another type of screening.
When it comes to COVID-19 it is important to remember, first and foremost, that despite the importance of the test, it is not a substitute for proper screening. Screening for this disease must include a careful history and assessment of signs and symptoms, such as fevers, cough, shortness of breath, chills, muscle pain, and loss of taste or smell.
Molecular Diagnostics vs. Serologic Testing
Part of the confusion about COVID-19 testing is that there are two types of tests. The first uses a long swab to collect material from the back of the nose where it meets the throat. This test, called molecular diagnostics by scientists, is looking for the virus itself. The clinical implications are that the infection is current or very recent and the virus itself is detectable. Much of the national conversation about testing relates to molecular diagnostics.
Serologic testing, on the other hand, is a blood test that looks for antibodies against the coronavirus. Antibodies are a specialized kind of protein that helps the body fight infection; they form the backbone of our natural response to many infections. Presence of COVID-19 antibodies indicates that the individual has had a prior infection.
One way to think about the different uses of these two types of testing is that molecular diagnostics (testing for the virus) would be an important part of a test, track, and trace strategy. Because this test indicates active infection, it can help health authorities manage an outbreak in real time and predict immediate health services needs. Serologic testing, in contrast, tends to look back in time, and likely has more utility in determining back-to-work status and helping public health officials understand how the disease has spread through the population.
Limitations to Testing
Not all tests are necessarily reliable and in fact may not give us the information we need. Molecular diagnostics (swab test for the presence of virus) are very fast, specific, and sensitive, but tend to be complex and may require a lab to process. There is also a risk of false negatives if the sampling technique is poor. Serologic testing (blood test for presence of antibodies) carries a risk of both false positives and false negatives, and the timing of testing is especially critical.
In the national response to the COVID-19 pandemic, there has been a lot of effort to develop and expand all types of testing. Both types of testing are the subject of active research and development, and researchers are looking at point-of-care rapid test versions of each. It is likely that both types of testing, once refined, will play an important role in the national response and by extension in correctional health care.
What Should You Do Right Now?
During a pandemic, correctional decision making is heavily influenced by clinical decision making; the two professional influences must work together and correctional leaders look to their medical staff for guidance. Along these lines, we get questions from the field related to testing and housing such as: Does a negative test mean it is OK to house in general population? Is a negative test required to release from quarantine? Does a negative test mean the patient can’t get sick from COVID-19 again? Does a positive test alone mean the person must be isolated? These are all excellent questions, and there are no easy answers.
We recommend you take the following steps:
CDC Discontinuation of Isolation for Persons with COVID-19 Not in Healthcare Settings: https://www.cdc.gov/coronavirus/2019-ncov/hcp/disposition-in-home-patients.html
For physicians and other clinical specialists: https://jamanetwork.com/journals/jama/fullarticle/2765837 OECD Policy Responses to Coronavirus (Covid-19): Testing for COVID-19: A way to lift confinement restrictions.
Brent Gibson is the chief health officer of NCCHC and the managing director of NCCHC Resources. NCCHC Resources, Inc., provides technical consulting services for correctional health care systems nationwide. As jails, prisons, and juvenile detention facilities strive to deliver constitutional health care, improve quality and reduce liability, NCCHC Resources can offer unique expertise from the world’s leaders in correctional health care. With our roots in the National Commission on Correctional Health Care – the nation’s leader in setting standards for correctional health services – NCCHC Resources offers unparalleled breadth, depth, experience, and perspective.
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