Both the PCR test and antigen test can be used to determine whether you have been infected with the COVID-19 virus. While it takes longer to get results, a PCR test is usually more accurate than an antigen test.
Generally, you may be tested for COVID-19 if you:
- Have any symptoms of COVID-19.
- Have been in contact with a confirmed COVID-19 case, meaning you were within six feet for 15 minutes or more of someone who tested positive for COVID-19.
How does the PCR test work?
The PCR test looks for the presence of the COVID-19 virus by detecting its genetic material (RNA) through a technique called reverse transcriptase-polymerase chain reaction (RT-PCR). Samples that can be collected for this test include:
- Nasal swab
- Throat swab
- Saliva sample
If the sample contains the virus, its RNA will be extracted. The RNA is converted to DNA and made into several copies. These DNA copies are then detected by a machine.
The PCR test is currently the most accurate test for diagnosing COVID-19 virus infection and has a low risk of false-negative results (a false-negative occurs when you get a negative PCR result even though you are infected with the virus).
The accuracy of the PCR test, like other viral tests, depends on factors such as:
- Technique used to collect the sample
- Stage of the illness when the sample was collected
- Whether the sample was transported to the lab under appropriate conditions
One drawback to this test is that results may come back positive even after you have recovered from the infection. This is because the test detects even a small amount of viral RNA even when you are longer infected there is no live virus.
PCR test results may be available within 24 hours, but it may take longer if the lab is located far away from the sample collection site or if the lab has a large sample load.
How does the antigen test work?
The antigen test detects bits of certain proteins, called viral antigens, present on the surface of COVID-19 virus. Samples are taken from nasal swabs.
This test is also referred to as a “rapid test” because results may be available much faster (within 15-60 minutes). One advantage of that is that it can allow for more immediate diagnosis and treatment if you test positive, since the antigen test is highly specific for COVID-19.
However, antigen tests have a high rate of false-negative results and are not as accurate as PCR tests. Since a negative antigen test result does not necessarily mean that you are not infected with the virus, your doctor may advise a PCR test to confirm the result.
Health Solutions From Our Sponsors
Top PCR Nasal Swab vs. COVID-19 Antigen Test Related Articles
Coronavirus COVID-19 Prevention: Test Your Medical IQWhat's really the best way to prevent the spread of new coronavirus COVID-19? Should wear a mask or not? Take this quiz to find out!
Coronavirus: How COVID-19 Affects Your BodyBy now, everyone knows about COVID-19. But do you know how it can affect your body?
COVID-19 (Coronavirus) Prevention TipsCOVID-19 is a novel coronavirus that spreads from person to person via infected respiratory droplets. The main symptoms of COVID-19 infection include cough, fever, and shortness of breath. Occasionally, people infected with COVID-19 may experience diarrhea, a sore throat, a runny or stuffy nose, or aches and pains. Avoiding contact with infected people, social distancing, not touching your face, frequent hand washing, cleaning, and disinfecting of frequently touched surfaces can help to reduce your risk of contracting the 2019 novel coronavirus.
COVID-19 Vaccine Myths and FactsThe FDA has granted Emergency Use Authorizations for COVID-19 vaccines that have been shown to be safe and effective as established by data from large clinical trials.
COVID-19 vs. Flu vs. ColdWhen you're feeling sick, it can be difficult to distinguish the symptoms of a COVID-19 infection from the symptoms of the common cold or the flu (influenza). While fever is common with the flu and COVID-19, sneezing is typically only associated with colds. Though sore throats are typical with colds, they are uncommon with COVID-19 infections and the flu.
How Do the COVID-19 Coronavirus Tests Work?Tests used for detection of SARS-CoV-2 (COVID-19) may use two methods to detect SARS-CoV-2 virus, the cause of COVID-19 disease, a debilitating and potentially deadly viral pneumonia. Genomic or molecular detection confirms the presence of viral DNA. The immunoglobulin or serology tests can tell whether or not you have been exposed to coronavirus, but not whether you are currently infected. Both tests administered in tandem can give you your complete COVID-19 infection status.
How Do You Know if You Have a Sinus Infection (Sinusitis) or COVID-19 Coronavirus?Learn how the signs and symptoms of a sinus infection are different from those caused by COVID-19.
How Do You Know if You Have Bronchitis or COVID-19 (Coronavirus)?What is the difference between bronchitis and COVID-19 (Coronavirus)? Learn how to recognize the symptoms of bronchitis and COVID-19 to help you treat either illness.
How Long Is COVID-19 Patient Contagious for?People infected with COVID-19 can still be contagious even when they stop feeling sick, so precautionary measures should continue for at least 2 weeks after symptoms disappear and until the COVID-19 test result is negative. Ideally, patients should be quarantined at home or an institution for 2 weeks after the symptoms completely disappear.
Lung Disease & Respiratory Health: Should I Get a COVID-19 Antibody Test?If you had COVID-19 symptoms but never got tested, or if you have long-term symptoms that just won't go away, you may want to get an antibody test. It can tell you if you've already had the virus. Here's what you need to know.
Lung and Respiratory: Signs That You May Have Had COVID-19Could you have already had COVID-19 and not know it? Learn some signs that might indicate just that.
How to Differentiate Between the Signs and Symptoms of COVID-19, Allergies, Cold, and Flu?Coronavirus disease or COVID-19 is an infectious disease caused by a newly discovered coronavirus called SARS-CoV-2. Most people with COVID-19 will experience a mild to moderate respiratory illness and recover without the need for intensive or special treatment. Serious illness is more likely in elderly people and those with underlying medical conditions such as heart disease, diabetes, chronic respiratory disease, and cancer.
Tests Available for COVID-19Getting tested for COVID-19 can identify you as a positive or negative patient of the disease. Remember no test is 100% accurate. Different methods of testing have been launched to trace COVID-19 infection.
What Drugs May Fight COVID-19? Drug Trials, Treatments, VaccinesWhat drugs could help fight coronavirus COVID-19? Clinical studies are ongoing for antiviral drugs like hydroxychloroquine, chloroquine remdesivir, lopinavir and favipiravir, as well as COVID-19 vaccines. Learn why anti-flu respiratory drugs and home remedies may prove useful to treat or prevent serious coronavirus infections.
What Is the COVID-19 Antibody Test For?The COVID-19 antibody test, also known as a serology test, is a blood test that looks for antibodies to determine whether you have had a recent or past infection of the virus that causes COVID-19.
COVID-19 (Coronavirus, 2019-nCoV)Infection with COVID-19 (2019 novel coronavirus, 2019-nCoV) causes respiratory problems in humans. Transmission of COVID-19 occurs mainly through contact with respiratory sections from an infected person, however, fecal contamination may also spread the virus. Symptoms start off flu-like and progress to coughing, fever, shortness of breath, shaking chills, headache, loss of sense of taste and/or smell, muscle pain, and sore throat. Treatment focuses on supportive care and symptom relief. COVID-19 vaccines are available.