COVID-19 Diagnostic Testing

Overview

Genetic-based tests, also known as molecular lab tests, check for the presence of genetic material from SARS-CoV-2, the virus that causes COVID-19. The most common method is reverse transcription polymerase chain reaction (RT-PCR), also called a nucleic acid amplification test (NAAT). These tests are highly accurate. Some PCR tests can be done at home, but most require a healthcare provider and lab equipment.

Key Features:

• Detect viral RNA
• Used widely for COVID-19 testing
• NAATs include PCR and similar technologies
• Provide accurate results

Test Type	Detects	Accuracy	Process Time
RT-PCR (Lab)	Viral RNA	High	Several hrs
RT-PCR (Home)	Viral RNA	High	Varies

Rapid Protein Detection Tests

These tests, commonly known as antigen tests, detect specific proteins from the COVID-19 virus. They can be done at home or in clinical settings and usually deliver results in 15–30 minutes. While convenient for quick screening, they’re less sensitive than molecular tests—especially in people without symptoms.

Pros:

• Fast results
• Easy to use

Cons:

• Lower sensitivity, especially for people without symptoms

Tests That Detect Multiple Respiratory Viruses

Some advanced diagnostic tests detect COVID-19, influenza A, and B from a single sample. These multiplex RT-PCR assays allow identification of multiple respiratory viruses without needing extra swabs or tests, which is useful during flu season or outbreaks.

Main Points

• Test more than one virus at once
• Save time and resources
• Commonly target COVID-19, influenza A, and influenza B

These tests reflect ongoing innovation in in vitro diagnostics (IVD), enabling fast and accurate detection of respiratory illnesses.

Purpose of Testing

People get tested for COVID-19 for many reasons, including when they have symptoms like fever, cough, or trouble breathing. Testing identifies whether symptoms are caused by COVID-19. Others may get tested after exposure to someone with the virus.

Waiting around five days after exposure improves result accuracy. Doctors or public health officials may recommend testing, especially for those with symptoms or high-risk exposure. Testing also protects vulnerable people—for example, before visiting someone at risk for severe illness.

Some people with COVID-19 don’t feel sick but can still spread the virus. Testing asymptomatic individuals can identify hidden infections and prevent further transmission. Anyone who tests positive—regardless of symptoms—should follow isolation guidelines.

Possible Problems

COVID-19 tests carry some risks, mainly false results.

• A false positive—though rare—may occur due to test issues or a person’s medical background. It can cause stress or unnecessary medical steps, but affects less than 1% of tests.
• A false negative means the test misses an infection, leading to potential spread if precautions are skipped. Repeat testing can reduce this risk.

Getting Ready for Testing

Before using a self-test, it helps to keep a few on hand. These are available in stores, pharmacies, and online. Check for FDA approval and expiration before use. The FDA’s website lists authorized tests.

When using a home test, carefully follow instructions to improve accuracy. If going to a test site, wear a mask—even if you don’t feel sick—to protect others. Pharmacies, clinics, and community centers offer testing services.

Checklist for Preparation

• Buy self-tests in advance.
• Confirm FDA approval and expiration.
• Read and follow all instructions.
• Wear a mask at testing locations.

What to Expect During COVID-19 Testing

A COVID-19 test usually involves collecting a sample from the nose, throat, or saliva. This helps healthcare providers determine next steps.

What to Bring to a Testing Location

Item	Purpose
Personal ID	Needed for registration.
Insurance (if asked)	Some sites request insurance, but it is often free.
List of symptoms (if any)	Helps provide necessary background.
Comfort items for children	Reduces stress for younger patients.

At-Home and On-Site Options

People can do tests at home or in community testing locations. At-home tests let people gather the sample themselves. At clinics or community centers, healthcare workers collect the sample. Local health departments organize community-based testing to make it easier for everyone to get tested.

Community-Based Testing and Health Departments

Some areas offer testing through local health departments or community events, bringing services closer to where people live. These options are especially helpful for people with limited mobility or transportation.

Role of the Health Department:

• Share testing locations, hours, and instructions.
• Answer questions and guide next steps.
• Provide updates via websites or phone lines.

How Samples Are Collected

Healthcare providers or individuals mainly gather COVID-19 samples in two ways:

• Swab Test: A long, narrow swab goes inside one nostril and rotates gently. Sometimes, the back of the throat is swabbed instead.
• Saliva Test: In some cases, individuals spit into a tube several times to provide enough sample for testing.

Test Type	How it Works	Who Collects the Sample	Sensitivity	Comfort Level
Nasal Swab	Swab placed in nostril or throat, then rotated	Healthcare provider or individual	High	Moderate discomfort
Saliva Test	Spit into a tube	Individual	Slightly lower	More comfortable

During the Test

• The process is quick and usually finished in under a minute.
• The person being tested needs to stay still.
• For swab tests, tilting the chin can help with a smooth sample collection.
• Medical staff may ask for help from family to keep children calm and steady.

What Patients Might Feel

Many people feel a bit nervous about having a swab put in their nose or throat. It may feel strange or tickle, and some people feel mild discomfort. The process usually takes only a few seconds. With saliva tests, the process is simpler and might be less nerve-wracking.

Tips for Children and Families

Children may be uneasy seeing staff in protective gear. Explain the process and why people look different. Help them sit still and bring comfort items.

Helpful Tips

• Offer reassurance.
• Bring comforting items (toy or blanket).
• Use distraction techniques like deep breathing.

Protective Measures by Care Providers

Healthcare workers wear masks, face shields, and protective gear to prevent the spread of germs.

Managing Patient Care

After the sample is collected, patients wait at home for results. Providers give advice on care, isolation, and when it’s safe to resume normal activities. Other tests may also be run to rule out illnesses with similar symptoms, like the flu.

Following Up on Results

Healthcare teams share results as soon as possible. If positive, they explain isolation and how to prevent spread. Providers also answer questions and offer support.

Test Outcomes

When Positive

A positive result confirms an active infection. It’s reliable—even if the person has no symptoms. Positive results from tests authorized under the FDA’s Emergency Use Authorization (EUA) are considered accurate.

Recommendation	Action
Stay isolated	Until fever-free without medicine for 24 hours.
Wear a mask	For 5 more days after symptoms improve.
Repeat testing	If you plan to be indoors in the company of others.
Severe symptoms	Follow advice from a healthcare professional.

People with weak immune systems may need longer isolation. If symptoms return, restart precautions.

When Negative

A negative result usually means no current infection, but false negatives are possible. The FDA recommends retesting in certain situations. If exposed or symptomatic, stay away from others and retest after 48 hours. If symptoms continue after two negatives, try a third test or use a different test type (like molecular testing).

Quick Tips

• Sensitivity: Describes how well the test correctly identifies positive cases.
• Specificity: Describes how well the test correctly identifies negative cases.

If results are unclear, consult a healthcare provider.