Fever, cough, sore throat: is it a bacterial or viral infection? The answer often decides whether you leave with an antibiotic, and it is surprisingly hard to call in the emergency room or at urgent care. On November 3, 2026, the FDA cleared a new version of the MeMed BV test, a blood test that reads your immune response and returns a result in about 15 minutes. Here is what the test measures, what the studies show, its limits, and what your own blood work (CRP, procalcitonin, white blood cell count) can already tell you.
What the FDA cleared
MeMed BV, developed by the Israeli company MeMed, was first cleared in the US in 2023 on its own small analyzer. The news is its wider reach: the new Access MeMed BV runs on Beckman Coulter's DxI 9000 and Access 2 immunoassay analyzers, which are already installed in many hospital and urgent care labs. According to the manufacturer and Healio, the clearance covers:
- adults and children as young as 90 days;
- suspected acute infection, typically seen in the emergency department, urgent care, or at hospital admission;
- a serum or plasma sample, with a result in as little as 15 minutes on the DxI 9000.
The result is always interpreted together with the physical exam and other tests. It is not a routine test you can order at a retail lab.
How it works: reading the immune response
Most infection tests look for the germ itself: a rapid strep test, a flu, COVID-19, or RSV PCR, a urine culture. MeMed BV does the opposite. It measures three proteins your own body makes, whose levels shift depending on whether it is fighting bacteria or a virus:
- TRAIL, a protein that rises mainly during viral infections;
- IP-10, another signal of the antiviral defense;
- CRP (C-reactive protein), the familiar inflammation marker, which tends to climb higher in bacterial infections.
An algorithm combines the three values into a score from 0 to 100. A low score points to a viral (or other non-bacterial) cause, a high score to a bacterial infection, and a middle zone is reported as equivocal. On its own, CRP can be high in both situations, which is why it does not always settle the question. Pairing it with two virus-sensitive proteins sharpens the distinction.
Why it matters: antibiotics and resistance
When doctors are unsure, many antibiotics are prescribed "just in case." Yet antibiotics do nothing against the viruses behind colds, flu, bronchiolitis, and most sore throats and bronchitis, and every unnecessary course helps resistant bacteria spread. According to the CDC, at least 28% of antibiotics prescribed in US outpatient settings are unnecessary, and most human antibiotic use happens outside the hospital.
A test that helps the clinician say "this is very likely viral" can make it easier to skip an antibiotic you do not need. A clearly bacterial result, on the other hand, supports treating quickly and looking further. Healio notes that the clearance came about a week after new CDC data on infections and deaths caused by antimicrobial-resistant germs.
What the test does not do
- It does not name the germ. A "bacterial" result does not tell which bacterium is involved or which antibiotic will work; urine cultures, blood cultures, or throat swabs are still needed.
- It is not a routine checkup test: the clearance targets emergency, urgent care, and hospital admission settings.
- Some results are equivocal, and some people have a viral and a bacterial infection at the same time.
- Used outside its intended setting (for example, to decide on blood cultures in the ER), it loses much of its accuracy, according to a 2026 study in the Journal of Clinical Microbiology.
- Much of the research was funded or co-authored by the manufacturer, so more independent studies are needed.
Recent advances
Host-response tests have been studied extensively over the past three years. The overall picture is encouraging, with important nuances.
- In the emergency department, a large US and Israeli study (Apollo, 2024) found the test closely matched the judgment of experts who reviewed each patient's full record. A "viral" result was especially reliable for ruling out a bacterial infection.
- A 2026 systematic review pooling sixteen studies confirmed these findings in adults and children, and observed that clinicians using the test reserved antibiotics more often for the patients who needed them.
- A pilot randomized trial in adults with lower respiratory infections (JUNO, 2025) suggested more targeted prescribing without more return visits or hospital admissions.
- In people over 65, who are often harder to diagnose, the test performed as well as in younger adults (pooled analysis, 2025).
- An economic model for France and Spain (2026) suggested that adding the test to the care of suspected pneumonia in the ER could avoid unnecessary antibiotics and tests and lower costs. It is a simulation, not a study of real patients.
- However, in adults hospitalized with a respiratory infection (2024), the test caught almost every bacterial infection but wrongly labeled many viral infections as bacterial: its value depends on who is being tested.
What it means for you: this type of test may increasingly complement CRP and procalcitonin in the ER, helping your care team decide faster whether an antibiotic makes sense.
Which tests can monitor or screen for a bacterial or viral infection?
Several tests help your clinician lean one way or the other. None is enough on its own.
| Test | What it shows | Main limitation |
|---|---|---|
| CRP (C-reactive protein) | General inflammation; a very high level points toward bacteria | Also rises in some viral infections, after injury, or with inflammatory diseases |
| Procalcitonin (PCT) | Rises mainly in bacterial infections; used in hospitals | Less useful in mild or localized infections |
| Complete blood count (CBC) with differential | Excess neutrophils: more often bacterial; excess lymphocytes: more often viral | The patterns overlap a lot |
| MeMed BV (TRAIL, IP-10, CRP) | Probability score for bacterial versus viral infection | Mainly in ER, urgent care, and hospitals; some results are equivocal |
| Urine culture, blood cultures, swabs | Identify the bacterium and the antibiotic that works (susceptibility testing) | Results take one to several days |
| Rapid strep test, PCR tests | Detect a specific germ (strep, flu, COVID-19, RSV) | Only find the germs they look for |
If your results include CRP, procalcitonin, or a CBC, read them alongside your symptoms and how long they have lasted: a single value rarely gives the answer, and the trend from one blood draw to the next is often more telling.
When to see a doctor
- Any fever in a baby younger than 3 months.
- A fever lasting more than three days, or symptoms that improve and then suddenly get worse.
- Shortness of breath, chest pain, a stiff neck, or a rash that does not fade when pressed.
- Burning when urinating together with fever or lower back pain.
- Any infection if you are pregnant, have a weakened immune system, or live with a chronic disease.
Call 911 for severe trouble breathing, bluish lips, fainting, or sudden confusion: these can be signs of sepsis.
Glossary
- Host response: the way your immune system reacts to an infection, which can be measured in the blood.
- TRAIL: an immune protein that rises mainly during viral infections.
- IP-10: a signaling protein released during the defense against viruses.
- CRP: C-reactive protein, made by the liver during inflammation.
- Procalcitonin: a protein whose blood level rises mostly in bacterial infections.
- Antibiotic resistance: the ability of bacteria to survive the antibiotics meant to kill them.
- Equivocal result: a score that points clearly toward neither bacteria nor a virus.
Frequently asked questions
Can a blood test tell if an infection is bacterial or viral?
It can help. CRP, procalcitonin, and the CBC give clues, and combined tests such as MeMed BV improve accuracy. None is perfect: your clinician always reads them together with your symptoms and exam.
Can I ask for the MeMed BV test?
It is mainly available in emergency departments, urgent care centers, and hospitals whose labs offer it. Whether it is used depends on the facility and on your clinician's judgment.
Does a high CRP always mean a bacterial infection?
No. CRP also rises with some viral infections, after surgery, and in inflammatory diseases. A very high level makes a bacterial cause more likely, but context and trends matter.
Does a "viral" result mean I do not need an antibiotic?
It makes a bacterial infection less likely, which often supports skipping one. The decision belongs to your clinician, who may reassess if your condition changes.
Does this test replace a rapid strep test or a urine culture?
No. Those tests identify a specific germ, while MeMed BV measures your body's reaction. The two approaches answer different questions and complement each other.
Sources
- Beckman Coulter Diagnostics. Beckman Coulter Diagnostics receives US FDA clearance for rapid bacterial vs. viral assay, November 3, 2026
- Healio. Bacterial or viral? FDA clears rapid test distinguishing type of infection, November 3, 2026
- CDC. Antibiotic use in the United States, September 15, 2025
- Bachur RG, Kaplan SL, Arias CA, et al. A rapid host-protein test for differentiating bacterial from viral infection: Apollo diagnostic accuracy study. JACEP Open, 2024. DOI: 10.1002/emp2.13167
- Moola S, Carrol ED, Rothman RE, et al. Diagnostic performance of the MeMed BV test to distinguish between bacterial and viral or other non-bacterial causes amongst ED and urgent care patients: a systematic review with meta-analysis. Diagnostics, 2026. DOI: 10.3390/diagnostics16121930
- Singer AJ, Hollander JE, Kean E, et al. Effect of host-protein test (TRAIL/IP-10/CRP) on antibiotic prescription and emergency department or urgent care center return visits: the JUNO pilot randomized controlled trial. Academic Emergency Medicine, 2025. DOI: 10.1111/acem.70031
- Gottlieb M, Orr N, Hamami S, et al. A host-protein test for differentiating bacterial from viral infection: diagnostic accuracy in elderly patients. JACEP Open, 2025. DOI: 10.1016/j.acepjo.2025.100245
- Borisenko O, Stas P, Maslov A, et al. Cost-consequence analysis of diagnostic strategies for suspected community-acquired pneumonia in France and Spain. Journal of Medical Economics, 2026. DOI: 10.1080/13696998.2026.2681380
- Dedeoglu B, Tanner AR, Brendish NJ, et al. Comparison of two rapid host-response tests for distinguishing bacterial and viral infection in adults with acute respiratory infection. Journal of Infection, 2024. DOI: 10.1016/j.jinf.2024.106360
- Sundaram S, Wahlig T, Arbefeville S, et al. Sensitivity and specificity of a rapid, point-of-care assay distinguishing bacterial from viral infections in acute care settings. Journal of Clinical Microbiology, 2026. DOI: 10.1128/jcm.00262-26
Other articles
- CRP (C-reactive protein): the inflammation marker
- Procalcitonin (PCT): the bacterial infection marker
- High CRP levels: causes, symptoms, and treatments
- Complete blood count (CBC): a full guide
- Sepsis: a blood test biomarker for earlier detection
- Urinary tract infection: symptoms, causes, and treatment
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