You wake up with a sore throat. By lunchtime you’re coughing. That evening you have chills and a fever.
So what is it? Flu? COVID? RSV? A common cold?
The frustrating answer is that symptoms alone often cannot reliably tell you.
Flu, COVID-19 and RSV can all cause overlapping symptoms, including:
- Cough
- Fever
- Chills
- Fatigue
- Headache
- Congestion
- Runny nose
- Sore throat
- Body aches
So when should you get tested? Testing is most useful when the result could change your treatment, help protect someone at higher risk or guide decisions about work, travel or close contact with others.
You Don’t Necessarily Need a Test for Every Cold
Most mild respiratory infections improve with supportive care.
If you have mild symptoms, are otherwise healthy and are recovering normally, identifying the exact virus may not always change what you do.
But there are situations where testing becomes much more useful.
Get Tested Early If You’re at Higher Risk
Testing matters most when the result could change treatment.
That includes people at higher risk of complications because of:
- Older age
- Chronic lung disease
- Heart disease
- Diabetes
- A weakened immune system
- Pregnancy
- Other significant chronic medical conditions
Why test quickly?
Because antiviral treatment for influenza and COVID works best when started early in the illness. CDC guidance notes that flu antivirals work best when started within the first 1 to 2 days after symptoms begin, while treatment for eligible higher-risk COVID patients should also begin as soon as possible.
Waiting several days to “see what happens” can narrow the treatment window.
If you’re high risk and develop flu-like symptoms, contact your healthcare provider early, even if your symptoms initially seem mild.
Test If the Result Will Change What You Do
Maybe you’re supposed to visit your 80-year-old mother.
Maybe you work around medically vulnerable patients.
Maybe someone in your household is immunocompromised.
Knowing whether you have a contagious respiratory infection may change decisions about work, gatherings, travel and contact with higher-risk family members.
Testing can provide useful information for those decisions. CDC also notes that respiratory testing can help guide treatment and decisions that reduce the chance of spreading illness to others.
Flu and COVID Can Be Treated
One reason testing can be useful is that influenza and COVID are not simply illnesses you always have to “ride out.”
Antiviral medications are available for appropriate patients.
But timing matters.
If treatment may be indicated, an earlier diagnosis can make a meaningful difference.
That is also why a primary care visit can be useful when symptoms are significant, you are at higher risk or you are unsure whether treatment is needed.
What About RSV Testing?
Most healthy adults with RSV experience an illness resembling a cold and will not require specific RSV treatment.
Testing tends to be more clinically important in certain situations, particularly in:
- Infants
- Older adults
- People with cardiopulmonary disease
- Immunocompromised individuals
- Patients with more serious illness
Your clinician can determine whether RSV testing would actually change your care.
What Is a Multiplex Respiratory Test?
Instead of testing for one virus at a time, some medical offices use multiplex testing.
One specimen can be tested for several respiratory viruses, such as:
- Influenza A
- Influenza B
- COVID-19
- RSV
This can be helpful because the symptoms overlap so much.
CDC notes that multiplex tests can help identify influenza, SARS-CoV-2 and RSV and support decisions about antiviral treatment and other clinical management.
A positive result may help your clinician decide whether antiviral treatment, monitoring or another approach is appropriate.
What If Your Home COVID Test Is Negative?
A single negative rapid antigen test does not always rule out COVID, particularly early in the illness.
If your symptoms fit and your first antigen test is negative, follow the manufacturer’s and FDA recommendations regarding repeat testing.
If you’re sick enough to need medical attention, do not let one negative home test prevent you from being evaluated.
You could have flu, RSV, strep throat, pneumonia or another illness entirely.
When Is a Sore Throat More Than a Virus?
Not every respiratory illness is viral.
Strep throat, for example, is caused by bacteria.
Depending on your symptoms and examination, your clinician may recommend strep testing, particularly when there is significant throat pain, fever, swollen lymph nodes or other findings that raise suspicion.
Antibiotics treat bacterial infections such as strep.
They do not treat flu, COVID, RSV or the common cold.
When Should You See a Doctor?
Consider medical evaluation if you have:
- High or persistent fever
- Difficulty breathing
- Wheezing
- Chest pain
- Significant dehydration
- Severe weakness
- Symptoms that improve and then suddenly worsen
- Persistent symptoms that aren’t improving
- A chronic medical condition that increases your risk
- Concern that you may need antiviral medication
Seek urgent or emergency care for severe difficulty breathing, bluish or gray lips or skin, severe chest pain, confusion, fainting or other signs of a medical emergency.
If you are unsure whether your symptoms need testing or treatment, RescueMD provides primary care services for acute illness and ongoing medical care.
Frequently Asked Questions
Who Should Get Tested Early for Flu or COVID?
Testing is especially useful when the result could affect treatment. People at higher risk of complications, including older adults, pregnant patients, people with chronic medical conditions and immunocompromised patients, should contact a healthcare provider early if they develop flu-like symptoms.
Do Adults Need an RSV Test?
Not always. Most healthy adults recover from RSV with supportive care. Testing is more useful in higher-risk patients or when illness is more severe and the result may change clinical management.
What Is a Multiplex Respiratory Test?
A multiplex respiratory test checks one sample for several viruses, such as influenza A, influenza B, COVID-19 and RSV.
What If My Home COVID Test Is Negative?
A single negative rapid antigen test does not completely rule out COVID. If symptoms continue, follow repeat-testing instructions and seek medical evaluation if you are significantly ill or at higher risk.
When Is a Sore Throat More Than a Virus?
A sore throat may be caused by a bacterial infection such as strep. A clinician may recommend testing depending on your symptoms, examination and risk factors.
When Should I See a Doctor for Flu, COVID or RSV Symptoms?
Seek medical evaluation for high or persistent fever, difficulty breathing, worsening symptoms, dehydration, chest pain, severe weakness or if you are at higher risk of complications.
Sick and Not Sure What You Have?
You should not have to diagnose yourself from a symptom chart on the internet.
RescueMD provides primary care for acute illnesses as well as ongoing medical care.
If you develop fever, cough, sore throat, congestion or other respiratory symptoms, our clinical team can determine whether testing is appropriate and help you understand the next step.
Feeling sick? Schedule a visit with RescueMD and let us help figure out what’s causing your symptoms and what you should do about it.