COVID-19 Symptoms and Testing – What Healthcare Professionals Need to Know

April 1, 2021
April 1, 2021

by Joanne Tate, BSN, RN, Accreditation and OSHA Standards Courseware Author, HealthStream

Many months have passed since that first confirmed case of COVID-19 was identified in the United States on January 22, 2020. With time, we rapidly learned a lot about the disease, including how SARS-CoV-2 is transmitted, how to protect ourselves and others, and common signs and symptoms of the disease. We are still learning, and information may change over the course of time as we learn more. This blog will review common symptoms and update you on testing options to help you determine who should be tested.

COVID-19 Symptoms

Symptoms can range from mild to severe. People with heart and lung disease, diabetes, and other chronic conditions are at greater risk of developing severe complications of COVID-19.

Symptoms may appear within 2 to 14 days after exposure to the virus. The CDC states that clinicians should use their judgment to determine if a patient has signs or symptoms compatible with COVID-19 and whether the patient should be tested.

People with the following symptoms may have COVID-19:

  • Fever or chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue
  • Muscle or body aches
  • Headache
  • New loss of taste or smell
  • Sore throat
  • Congestion or runny nose

Serious symptoms of COVID-19 are hypoxia and ventilation failure which require immediate medical attention. Patients present with trouble breathing, cyanosis, persistent pain or pressure in the chest, new confusion, or difficulty in staying awake. In terms of patient and public education, the CDC has an app on their website to help individuals make decisions about seeking medical care and testing. You can refer individuals to this app, called the Coronavirus Self-Checker.

Source Control

Transmission can occur via asymptomatic or pre-symptomatic individuals and therefore, the CDC recommends that patients and visitors wear a cloth mask (preferably their own) upon entering and while in your facility. If people do not come with a mask, one can be offered as supplies allow. This is source control. Remind patients and visitors to wash their hands if they need to adjust their mask to avoid cross-contamination of surfaces or self-contamination if they touch their eyes, nose, or mouth.


Keep in mind that testing recommendations from the CDC are based on what is known about COVID-19 and is subject to change as more is learned.

There are two types of tests:

  1. Viral Testing: Tests for the virus itself (i.e., nucleic acid or antigen testing) and
  2. Diagnostic Testing: Tests for antibodies to the virus

Let’s take a closer look at each of these tests.

1. Viral Testing 

Viral testing is recommended by the CDC to detect acute infection. There are two types of viral tests.

a. Nucleic Acid Amplification Tests

The molecular Reverse Transcription-Polymerase Chain Reaction (RT-PCR) detects nucleic acids from SARS-CoV-2. As you may recall from biology, nucleic acids store and transfer genetic information and are present in DNA and RNA.

b. Antigen Tests

Antigen tests detect proteins on the surface of the virus.

2. Diagnostic Testing

Diagnostic testing is done for people with symptoms or those who are asymptomatic with known or suspected recent exposure to SARS-CoV-2.  This helps to control transmission by using quarantine or isolation measures.

Viral testing also helps to determine if the disease is resolved and when to discontinue transmission-based precautions in health care settings, when to stop isolation outside of health care, and when healthcare workers can return to work after being infected. Viral tests that have received Emergency Use Authorization ( EUA) can be found on the U.S. Food and Drug Administration (FDA) website. (U.S. Food & Drug Administration, 2020)

Testing should also be done for vulnerable populations who reside in close quarters for extended periods of time (e.g., long-term care facilities, correctional and detention facilities) and/or settings where critical infrastructure workers (e.g., healthcare personnel, first responders) may be disproportionately affected. Early identification could reduce the risk of widespread transmission in these situations.

The CDC specifically recommends testing for all neonates born to women with COVID-19, regardless of whether there are signs of infection in the neonate.


Viral testing is also used for surveillance if it is conducted among asymptomatic individuals without known or suspected exposure. It helps with:

  • Early identification of infection
  • Identification of transmission hot spots
  • Characterization of disease trends

Most viral tests require the use of a nasal swab to collect the specimen which can be tested at the point of care or sent to a laboratory. For instance, one point of care test takes advantage of Abbott’s ID NOW platform, already in thousands of doctors’ offices across the country. It offers results within a few minutes. Laboratory testing may take 1-2 days once received by a lab.

Proper collection is one of the most important steps in diagnosing any disease. The CDC is now recommending nasopharyngeal swabs for collection although oropharyngeal remain an acceptable specimen type.  

Providers are encouraged to work with their local or state health departments to coordinate testing through public health laboratories. Providers may also use their own test if they have received an EUA from the FDA to do so. All positive tests should be reported. Specimen collectors and lab personnel should be aware of and follow storage and shipping requirements.

Antibody Testing

Antibody or serology testing is not authorized by the FDA to diagnose COVID-19. This is because antibody development is an indicator of an immune response to an exposure to some antigen and not the virus itself. It may take 1-3 weeks for antibodies to develop in an infected person, and if tested before antibodies develop, the test will yield negative results.  A test may also yield negative results if the individual being tested has a weakened immune response. A person can react falsely positive to an antibody test if the individual was infected with a coronavirus other than SARS-CoV-2, such as with the common cold. Testing for other possible causes of symptoms, such as influenza, may rule out COVID-19, although it is possible for a person to be co-infected with both viruses at the same time.

There is value in the antibody test though, if used together with a viral diagnostic test because the antibody test can support a clinical assessment for people who present late in their illness, such as with children who are suspected to have post-infectious syndrome (multisystem inflammatory syndrome in children) caused by SARS-CoV-2. Antibody tests can also help determine whether the individual being tested was previously infected—even if that person never showed symptoms. A positive result should not be interpreted that the person is immune and does not need to maintain social distancing, use of PPE, or other such measures.

Antibody testing may be used in individuals who have recovered from COVID-19 for evaluation when considering convalescent plasma donations.

Antibody tests that have been approved under an EUA can be found on the FDA website. (U.S. Food & Drug Administration, 2020). The American Medical Association recommends that physicians are aware of the regulatory status of tests and have a good understanding of antibody test limitations and potential results.

Antibody Testing and Public Health

Serology testing is used for surveillance to help us understand how many SARS-CoV-2 infections have occurred:

  • At various points in time
  • In different areas of the country
  • Within various populations

Antibody tests can help us understand the dynamics of SARS-CoV-2 transmission in the general population and identify groups at higher risk. It can also help us understand:

  • How much of the U.S. population has been infected
  • How much the infection rates are changing over time
  • Risk factors associated with SARS-CoV-2
  • How many U.S. citizens had mild or no symptoms
  • How long antibodies can be found after SARS-CoV-2 infection

If many people are tested using the antibody test, it can inform physicians and researchers of how the immune response develops and whether or how long, a person who has recovered from the virus is at a lower risk of infection if they are exposed to the virus again. We still do not know the answer to this.

The CDC is conducting seroprevalence surveys (investigations using serology testing) on a large scale in certain geographic areas, in some communities, and in specific populations. These investigations will help the CDC determine the incidence of SARS-CoV-2 infection and will guide control measures such as social distancing. By using seroprevalence surveys, the CDC can learn about the total number of people that have been infected, including those infections that might have been missed because they had mild or no symptoms and didn’t seek medical care.

The CDC is collaborating with other government agencies to evaluate the performance of commercially manufactured antibody tests. Some of these tests have received EUA from the FDA.

The CDC, the FDA, and other federal, state, and local agencies are playing a critical role in protecting the public’s health during the COVID-19 pandemic. Learning all that you can and staying informed through the federal guidance sites is the responsibility of every healthcare professional. The reference list below provides you with links to key topics discussed in the article.

Free COVID-19 Resources from HealthStream

To support caregivers and healthcare organizations as they respond to the COVID-19 pandemic, HealthStream is offering a collection of carefully curated courses to all customers for free. Likewise, Using HealthStream’s Channels platform for video learning, we have a created a free-access COVID19 Channel in response to the COVID19 pandemic, specifically to support healthcare workers and their families. It contains a collection of curated videos provided by HealthStream and HealthStream’s content partners from several trusted sources on YouTube, such as the CDC and Mayo Clinic.


  • American Medical Association. (2020, May 14). Serological testing for SARS-CoV-2 antibodies. Retrieved June 18, 2020, from American Medical Association:
  • Centers for Disease Control and Prevention. (2020, June 2). Interim Clinical Guidance for Management of Patients with Confirmed Coronavirus Disease (COVID-19). Retrieved June 19, 2020, from Centers for Disease Control and Prevention:
  • Centers for Disease Control and Prevention. (2020, May 22). Interim Guidelines for Collecting, Handling, and Testing Clinical Specimens for COVID-19. Retrieved June 19, 2020, from Centers for Disease Control and Prevention:
  • Centers for Disease Control and Prevention. (2020, May 23). Interim Guidelines for COVID-19 Antibody Testing. Retrieved June 18, 2020, from Centers for Disease Control and Prevention:
  • Centers for Disease Control and Prevention. (2020, June 13). Overview of Testing for SARS-CoV-2. Retrieved June 18, 2020, from Centers for Disease Control and Prevention:
  • Centers for Disease Control and Prevention. (2020, May 23). Serology Testing for COVID-19 at CDC. Retrieved June 18, 2020, from Centers for Disease Control and Prevention:
  • Centers for Disease Control and Prevention. (2020, May 23). Test for Past Infection (Antibody Test). Retrieved June 18, 2020, from Centers for Disease Control and Prevention:
  • Office of the Assistant of the Secretary for Health. (n.d.). Guidance – Proposed Use of Point-of-Care (POC) Testing Platforms for SARS-CoV-2 (COVID-19). Retrieved June 18, 2020, from Centers for Disease Control and Prevention:
  • U.S. Food & Drug Administration. (2020, June 17). FAQs on Testing for SARS-CoV-2. Retrieved June 18, 2020, from
  • U.S. Food & Drug Administration. (2020, June 18). In Vitro Diagnostics EUAs. Retrieved June 19, 2020, from U.S. Food & Drug Administration:

PLEASE NOTE: The information in this blog post was considered current at the time of its publishing, 6/30/20. However, the COVID-19 pandemic is an ever-evolving disaster due to new findings, data, and availability of resources. Please refer to the CDC website for the latest detailed information when you need it.


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