Why This Study Matters
Antibiotics are among the most commonly prescribed medicines in primary care, but they do not help viral infections and can contribute to antimicrobial resistance when used unnecessarily. Antimicrobial resistance is a major global health threat because it makes infections harder to treat and can lead to longer illness, more complications, and higher healthcare costs.
Rapid multiplex respiratory microbiological point-of-care testing, or RM-POCT, is designed to help clinicians quickly identify whether a respiratory infection is caused by a virus or certain bacteria. The hope is that if clinicians have faster and more specific information, they may be able to avoid prescribing antibiotics when they are unlikely to help, while still treating patients who truly need them. This trial asked a simple but important question: can RM-POCT safely reduce same-day antibiotic prescribing in routine primary care?
What the Researchers Studied
This randomized clinical trial was carried out in 16 general practices in Southwest England between December 2022 and April 2024. Patients were eligible if they were 12 months of age or older, had an acute respiratory tract infection lasting 21 days or less, and either the patient or clinician thought antibiotics were needed or might be needed.
A total of 552 patients were enrolled. Their average age was 40 years, and 63% were female. Participants were randomly assigned in equal numbers to one of two groups:
1. RM-POCT group: patients received a rapid respiratory panel test that looked for 19 viral pathogens and 4 atypical bacteria, with results available in about 45 minutes.
2. Usual care group: patients received standard clinical assessment without the rapid test.
The study team and statisticians were blinded to group assignment during analysis, which helps reduce bias.
How the Test Worked
The RM-POCT used in this study is a multiplex molecular test, meaning it can search for several pathogens at once from a respiratory sample. In practical terms, this kind of test can provide a clinician with much more microbiological information than a routine office visit alone.
The logic behind the test is straightforward: if a viral cause is identified, antibiotics are usually unnecessary. If a bacterial pathogen associated with respiratory disease is found, a clinician may be more confident in prescribing treatment. However, real-world prescribing decisions are influenced by more than test results alone, including symptom severity, patient expectations, and clinical caution.
Main Findings
The main outcome was same-day antibiotic prescribing. Antibiotics were prescribed on the day of the visit to 124 participants in the RM-POCT group and 124 participants in the usual care group. In both groups, this represented 45% of participants.
In statistical terms, the odds ratio was 1.00, with a 95% confidence interval of 0.71 to 1.41, and the P value was greater than .99. In plain language, this means the rapid test did not reduce immediate antibiotic prescribing compared with usual care.
The study also examined safety, using patient-reported symptom severity on days 2 to 4 after the visit. There was no meaningful difference between groups in symptom severity, with a difference in means of 0.09 and a 95% confidence interval from -0.10 to 0.27. This suggests that using the rapid test did not worsen short-term patient outcomes.
Subgroup Results: Where the Test May Have Helped
Although the overall result was negative, some subgroup analyses suggested that the test may have influenced prescribing in specific situations.
When a virus was detected, antibiotic prescribing was more likely to be reduced in the RM-POCT group than in usual care. The odds ratio was 0.35, with a 95% confidence interval of 0.20 to 0.63, and the interaction P value was less than .001. This is biologically and clinically plausible, because a confirmed viral result can reinforce the decision not to prescribe antibiotics.
There was also some evidence of reduced prescribing among participants with chronic lung disease, with an odds ratio of 0.55 and a borderline interaction P value of .046. However, this finding should be interpreted cautiously because subgroup analyses are more vulnerable to chance findings.
By contrast, the test did not clearly reduce prescribing in children younger than 16 years, and it did not help when patients and clinicians disagreed about whether antibiotics were necessary. These results highlight the complexity of antibiotic decisions in primary care, where test information may not override clinical judgment, parental concern, or patient preference.
What the Results Mean in Practice
This trial shows that introducing a rapid respiratory microbiological test into primary care does not automatically lead to fewer antibiotic prescriptions. Even when clinicians had access to a test result within about 45 minutes, overall prescribing remained unchanged.
There are several possible reasons. First, clinicians may still prescribe antibiotics because of uncertainty about clinical deterioration, especially when patients appear unwell or have risk factors. Second, not all respiratory infections are caused by pathogens included in the panel. Third, positive viral results do not always rule out bacterial co-infection. Finally, prescribing decisions are often shaped by concerns about safety, time pressures, and expectations from patients or families.
Importantly, the test also did not worsen short-term symptoms, which suggests that it may be safe to use in this setting even if it does not reduce prescribing overall. Safety is crucial when evaluating any strategy meant to reduce antibiotic use.
Strengths of the Study
This study had several important strengths. It was randomized, which is the best design for testing whether an intervention causes a change in practice. It was conducted in ordinary general practices rather than an artificial research environment, making the findings more relevant to everyday care.
The sample size was reasonable, all participants had primary outcome data, and the trial included both children and adults. The researchers also assessed symptoms after the visit, allowing them to examine whether withholding or reducing antibiotic use might have affected recovery.
Limitations to Keep in Mind
As with any trial, there are limitations. Safety outcome data were not available for everyone, which means some uncertainty remains about symptom reporting. The study was conducted in one region of England, so the results may not fully apply to other healthcare systems, where access to testing, prescribing patterns, and patient expectations may differ.
Also, the trial tested one specific RM-POCT platform and one implementation model. Different tests, different respiratory seasons, or different clinical workflows might produce different effects. In addition, antibiotic use is only one outcome; the study did not fully address whether the test improved diagnostic confidence, patient satisfaction, healthcare utilization, or longer-term antibiotic stewardship.
Clinical and Public Health Implications
For clinicians, the message is nuanced. Rapid respiratory testing can provide useful information, especially when it identifies a virus and helps explain why antibiotics may not be needed. But this trial suggests that test results alone may not be enough to change prescribing behavior in primary care.
For health systems, the study indicates that technology should not be expected to solve antibiotic overuse by itself. If RM-POCT is introduced, it may need to be paired with other strategies such as clinician education, shared decision-making tools, clear prescribing guidelines, and communication support to help explain viral diagnoses to patients.
For patients and families, the findings reinforce an important point: many respiratory infections are viral and get better with time, fluids, rest, and symptom-relief measures rather than antibiotics. Appropriate use of antibiotics remains essential to protect individual patients and the broader community.
Bottom Line
In this randomized clinical trial of patients with respiratory tract infections in primary care, a rapid multiplex respiratory microbiological point-of-care test did not reduce same-day antibiotic prescribing and did not worsen short-term symptom outcomes. The test may have helped reduce antibiotic use when a virus was detected, but overall it was not enough to change practice across the full study population.
The study adds valuable evidence to the growing field of rapid diagnostics and antimicrobial stewardship. It suggests that faster microbiological information can be helpful, but changing antibiotic prescribing in primary care likely requires more than a test result alone.