How Coronavirus (COVID-19) Is Diagnosed

How to know if you have this infection

The novel coronavirus, or COVID-19, has been spreading worldwide, resulting in growing numbers of infected individuals since late 2019 and increased mortality numbers since early 2020.

So far, experts have seen that while there are severe cases, the infection is usually mild with non-specific symptoms. And there are no trademark clinical features of COVID-19 infection. Known exposure to someone who has been infected with the virus along with cough, congestion, fever, and other flu-like symptoms may raise concern and prompt diagnostic testing. Because the virus is spreading, it is becoming more likely that a person could have been exposed without knowing it or without traveling.

Diagnosis of COVID-19 involves laboratory tests. Once someone has been diagnosed with the coronavirus, additional diagnostic tests may be done to determine the severity of the infection.

COVID-19 Diagnosis Process
Verywell /  Nusha Ashjaee

The indications for testing are evolving as more information is being gathered about this infection.

Who Can Get Tested?

The Centers for Disease Control and Prevention (CDC) issued tiered criteria for getting tested, and these criteria are evolving.

High-priority criteria include:

  1. Hospitalized patients who have signs and symptoms compatible with COVID-19
  2. Healthcare workers and first responders who show symptoms
  3. Residents in long-term care facilities or group housing who show symptoms

Priority criteria include:

  1. Anyone with potential COVID-19 symptoms of fever, cough, shortness of breath, chills, muscle pain, new loss of taste or smell, vomiting or diarrhea, and/or sore throat
  2. People without symptoms prioritized by health departments or clinicians

Steps to Getting Tested

With organizations like the Cleveland Clinic adapting CDC testing guidelines and methods for their own use, COVID-19 testing is beginning to shift from something done at the state level to something that can be done locally. Still, because of capacity issues and to prevent the spread of infection, you're discouraged from just walking into a doctor's office and asking for a test.

"Please, do everything you can not to show up without a doctor’s order," says Cleveland Clinic's Brian Rubin, MD, PhD, Chairman of the Pathology and Laboratory Medicine Institute in an interview shared with Verywell. Instead, he suggests using a telehealth service to have your symptoms screened by a doctor remotely, or scheduling an in-person consultation with your doctor.

If you think you may be sick but haven't talked to a healthcare provider yet, use our printable Doctor Discussion Guide below to help prepare you for your appointment.

Coronavirus (COVID-19) Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Old Man

Types of Tests

In the United States, the CDC was the first to offer a COVID-19 test. Private companies have also begun manufacturing tests. These tests can be used to diagnose an infection because they detect the genetic material of the virus itself.

CDC 2019-nCoV Real-Time Reverse Transcriptase RT-PCR Diagnostic Panel 

The U.S. Food and Drug Administration (FDA) first authorized a COVID-19 test created by the CDC that can detect viral genetic material.

If you need this test, a healthcare provider will collect a sputum sample as well as nasopharyngeal (nasal passages) and oropharyngeal (back of the throat) swab samples to send to an authorized laboratory for testing. The swab samples are collected by swabbing the secretions from the back of the mouth and the nose. 

If you have this test, your sample will be sent to an approved laboratory to be tested. According to the CDC, “The state and local health department will assist clinicians to collect, store, and ship specimens appropriately, including during afterhours or on weekends/holidays.”

Your doctor can contact the local or state health department for guidance with your testing.

Pixel by LabCorp COVID-19 Test Home Collection Kit

LabCorp is the first to receive EUA from the FDA for a COVID-19 diagnostic test with a home-collection option. On April 21, the FDA re-issued its EUA for the LabCorp COVID-19 RT-PCR Test, initially granted on March 16, extending it to a version with a home specimen collection.

The kit contains nasal swabs and saline for patients to collect their own samples, which they must send back to LabCorp in an insulated package. LapCorp will test for active COVID-19 infection, and patients can access their results online.

The test costs $119. It is currently only available to healthcare professionals, but will be made available to consumers who have a doctor's order in the coming weeks.

As of March 2, the Cleveland Clinic began using publicly-available information from the CDC to bring a version of the test on-site. That means testing can be done faster and results come in quicker: in 8 to 12 hours instead of 3 to 4 days. This is important for getting people appropriate treatment and isolating those who need to be isolated. The test can even be done via drive-through at Cleveland Clinic locations—but a doctor's order is still necessary.

Cepheid Xpert Xpress SARS-CoV-2 Test

Cepheid's test is the first rapid point-of-care test for COVID-19 to earn Emergency Use Authorization (EUA) from the FDA. Results are delivered to patients in the place where they received the test—whether that's a hospital, urgent care center, or emergency room—in a matter of hours. This eliminates the step of having a sample sent to a lab, greatly speeding up the process.

Abbott ID NOW COVID-19 Rapid Test

Abbott Laboratories introduced a rapid test that can show positive results in 5 minutes and negative results in 13 minutes. It has earned EUA from the FDA.

Hologic Panther Fusion SARS-COV-2 Assay

Hologic also received EUA from the FDA for its COVID-19 diagnostic test. It was created in less than two months with support from the U.S. government’s Biomedical Advanced Research and Development Authority (BARDA) and has been shipped to labs across the country.

Quest Diagnostics' SARS-CoV-2 RNA, Qualitative Real-Time RT-PCR

Quest Diagnostics has introduced a test for physicians and healthcare providers to order. Quest will only analyze results, not collect respiratory specimens or see patients. This test also has FDA EUA.

In addition to these tests, the FDA has granted Emergency Use Authorization (EUA) to dozens of COVID-19 diagnostic tests. See the full list here.

Results

If your test is positive: This means that you have been infected by the virus. But it doesn’t necessarily mean that COVID-19 is the cause (or only cause) of your illness. A co-infection with another virus or bacteria could be the cause of your symptoms.

If your test negative: Other factors are important to help confirm you are truly free of COVID-19, such as your symptom history and clinical examination. You may have been infected by the virus, but its presence could be undetected in your sample. 

So far, Dr. Rubin says about 3% to 3.5% of Cleveland Clinic's COVID-19 tests are positive—a lower rate than he expected.

Antibody Tests

A new type of testing is used to detect antibodies to the COVID-19 virus. These tests can identify whether a person previously had the infection, but their reliability has not yet been established and they are not yet in wide use.

Self-Checks

Your own assessment of your risk of infection involves staying up to date on your exposure risk. If you have been to places where the illness has been identified or if you have interacted with people who were infected or exposed to the virus, you could be at risk. Again, because the virus is spreading rapidly and has increased throughout the United States and the whole world, you could have been exposed without knowing it.

You can also monitor your own health for signs of COVID-19 infection. Things to look out for include:

  • Fever
  • Cough
  • Shortness of breath
  • Other breathing difficulties
  • Chills
  • Repeated shaking with chills
  • Muscle pain
  • Headache
  • Sore throat
  • Loss of sense of smell or taste

Keep in mind that these symptoms are very common and can occur with sinusitis, pneumonia, bronchitis, or any viral or bacterial respiratory infection, including the flu.

Because severe cases of COVID-19 infection can cause pneumonia, acute respiratory distress syndrome, kidney failure, and even death, it is important that you are especially vigilant about any rapid decline in your health or sudden worsening of symptoms. 

Physical Examination

When you go to see your doctor, they will perform a medical history and a physical examination.

Your examination will include:

An evaluation of your chest sounds: Lung infections and lung disease can cause characteristic changes in chest sounds such as crackling or wheezing. Your doctor can hear these sounds with a stethoscope. Keep in mind that the presence or absence of abnormal breath sounds does not confirm or rule out an infection with COVID-19.

Evaluation of respiratory distress, signs of dyspnea (shortness of breath): Advanced lung infections can make you short of breath and may make it difficult to breathe. If you are struggling to breathe, your doctor may notice that you are using accessory muscles to help you as you inhale. This is a sign of advanced lung disease or a severe infection.

Tachypnea (rapid respiratory rate): Sometimes lung problems can cause you to breathe rapidly, which is a sign of severe lung disease. A rate above 12 to 20 breaths per minute is considered high for an adult.

The doctor will also check your temperature for a fever.

Labs and Tests

Depending on your symptoms, additional tests may be needed to evaluate possible complications of your infection. Keep in mind that these tests aren’t used to diagnose COVID-19, but may be needed if the effects become severe.

  • Complete blood count (CBC): Measures your white blood cells (WBCs) and red blood cells (RBCs).
  • Pulse oximeter: A non-invasive test that can give your doctors a general idea of your oxygen level.
  • Arterial blood gas (ABG): A blood test that can show more precise measures than a pulse oximeter.
  • Electrolyte levels: Your doctor may order this test if you are showing signs of severe illness.

Imaging 

Chest imaging studies, including chest X-ray and chest computerized tomography (CT) may show changes with COVID-19 infection, but these changes are not specifically diagnostic of this infection, and can be present with other lung conditions like pneumonia and bronchitis.

Both sides of the lungs are usually involved about equally. With COVID-19 infection, the lungs often have the appearance of lung inflammation that is usually described as ground-glass opacity on a CT because it looks like the lungs are obscured by ground glass. This is a relatively common pattern seen with other lung infections too.

Differential Diagnosis

One of the challenges when it comes to COVID-19 infection is that it presents in a way that is very similar to other viral and bacterial respiratory infections, including colds, the flu, and strep throat. The symptoms don’t necessarily distinguish the illnesses from each other.

It's important to note that not only do the illnesses present similarly but that colds and the flu are currently far more common than COVID-19 in the U.S.

Your doctor may order a flu test or a test for strep throat if you seem likely to have these other illnesses based on your exposures and risk factors.

A Word From Verywell

While the eventual impact of COVID-19 isn’t certain, testing can help by getting prompt medical care for those who are at high risk of developing a fatal infection. If you have lung disease, heart disease, or a weakened immune system, an infection with COVID-19 is especially dangerous for you. However, the infection can be severe even if you are otherwise healthy. Keep in mind that you may still be at risk of newly contracting the infection even after you have a negative test that doesn’t show evidence of the virus.

Feelings of fear, anxiety, sadness, and uncertainty are normal during the COVID-19 pandemic. Being proactive about your mental health can help keep both your mind and body stronger. Learn about the best online therapy options available to you.

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Article Sources
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