Flu, COVID or RSV? What a Rapid Test Tells You

Flu, COVID-19 and RSV start out looking a lot alike: fever, cough, sore throat, aches and tiredness. You often can't tell them apart from symptoms alone, which is where a rapid test helps. A positive result tells you which virus you have, and that can change your treatment options, how long to stay home, and who around you should be careful.

Flu symptoms vs. COVID symptoms vs. RSV symptoms

All three are respiratory viruses that spread the same way and peak in fall and winter. There are some differences in how they tend to show up, but plenty of overlap:

• Flu (influenza): usually comes on suddenly, often within hours. High fever, chills, body aches, headache, exhaustion, dry cough and sore throat. People often describe feeling like they were hit by a truck.
• COVID-19: can start gradually or suddenly, and ranges from very mild to severe. Fever or chills, cough, sore throat, congestion, fatigue, headache and aches. A new loss of taste or smell is a clue, though it's less common than it once was.
• RSV (respiratory syncytial virus): in most older children and healthy adults, it looks like a cold: runny nose, cough, sneezing, mild fever. It can be serious in babies, older adults and people with heart or lung conditions, where it may cause wheezing and trouble breathing.

Because the symptoms overlap so much, guessing isn't reliable. It's also possible to have more than one virus at once.

What does a rapid test tell you?

A rapid test checks a swab from your nose or throat for proteins from a specific virus, and gives a result during the visit. At AfterOurs, rapid flu and COVID-19 testing is done in the exam room as part of a sick visit when a clinician thinks it will help.

What the result means:

• A positive result is reliable. It tells you that virus is very likely the cause.
• A negative result is less certain. Rapid tests can miss an infection, especially in the first day or two of symptoms, when there's less virus to detect. A clinician may still treat based on your symptoms and what's going around, or suggest testing again.

If you've already tested negative on a home COVID-19 test, that's useful information, but it doesn't rule COVID-19 out. Repeat home tests 48 hours apart are more reliable than a single test.

Why does it matter which virus it is?

For many healthy people, the care at home is the same: rest, fluids and fever relief. But knowing the cause helps in a few ways:

• Antiviral medicine. Prescription antivirals are available for flu and for COVID-19. They work best when started early, usually within the first couple of days of flu symptoms and within 5 days for COVID-19, and they're mainly recommended for people at higher risk of getting very sick. There's no routine antiviral for RSV in adults.
• Avoiding antibiotics that won't help. All three are viruses, so antibiotics don't treat them. A clear viral result can save you a prescription you don't need.
• Protecting people around you. Knowing it's flu or COVID-19 helps you decide when to go back to work or school and whether to keep away from a baby, a grandparent or someone with a weakened immune system.

A clinician can examine you, decide which tests make sense, and discuss treatment.

Who should get checked soon?

Come in early, ideally within the first day or two, if you're at higher risk of complications. That includes:

• Adults 65 and older
• Pregnant people
• Young children, especially under 2
• People with asthma, COPD, heart disease, diabetes, kidney disease or a weakened immune system

Anyone should come in if symptoms are getting worse instead of better after a few days, if a fever goes away and then comes back, or if a cough lingers for weeks. Our cold and flu and COVID-19 pages cover what we treat.

If your symptoms are mild and you mostly want advice, a telehealth video visit is $75 self-pay. Rapid tests need an in-person visit.

Call 911 or go to the ER if you or your child has trouble breathing or shortness of breath, chest pain or pressure that won't go away, bluish or gray lips or skin, new confusion or trouble waking up, a seizure, severe dehydration (no urine in 8 hours), or, in a baby, fast breathing, pauses in breathing, ribs pulling in with each breath, or refusing to feed.

What does testing cost?

Rapid tests are done as part of a sick visit. Self-pay, a standard visit is $175, a visit with one moderate service such as a rapid flu test is $250, and the most a visit costs is $330. The cost and insurance page explains the tiers. We contract with all major commercial and government plans, including Colorado Medicaid and Medicare. We can't guarantee a commercial plan has us in network, and if you're out of network or your benefits are denied, we bill you at our self-pay rates.

Where to find us

Four clinics across metro Denver, all ages welcome, se habla español:

• Hampden (Southeast Denver): 8 AM–11 PM daily
• Littleton: 8 AM–11 PM daily
• Thornton: 8 AM–11 PM daily
• Highlands: Mon–Fri 5–11 PM, Sat–Sun 8 AM–11 PM

Walk in, or book online.