The Clinical Utility of Point-of-Care Tests for Influenza in Ambulatory Care: A Systematic Review and Meta-analysis

Abstract

Background: Point-of-care tests (POCTs) for influenza are diagnostically superior to clinical diagnosis, but their impact on patient outcomes is unclear.

Methods: A systematic review of influenza POCTs versus usual care in ambulatory care settings. Studies were identified by searching six databases and assessed using the Cochrane risk of bias tool. Estimates of risk ratios (RR), standardised mean differences, 95% confidence intervals and I2 were obtained by random effects meta-analyses. We explored heterogeneity with sensitivity analyses and meta-regression.

Results: 12,928 citations were screened. Seven randomized studies (n = 4,324) and six non-randomized studies (n = 4,774) were included. Most evidence came from paediatric emergency departments. Risk of bias was moderate in randomized studies and higher in non-randomized studies. In randomized trials, POCTs had no effect on admissions (RR 0.93, 95% CI 0.61-1.42, I2 = 34%), returning for care (RR 1.00 95% CI = 0.77-1.29, I2 = 7%), or antibiotic prescribing (RR 0.97, 95% CI 0.82-1.15, I2 = 70%), but increased prescribing of antivirals (RR 2.65, 95% CI 1.95-3.60; I2 = 0%). Further testing was reduced for full blood counts (FBC) (RR 0.80, 95% CI 0.69-0.92 I2 = 0%), blood cultures (RR 0.82, 95% CI 0.68-0.99; I2 = 0%) and chest radiography (RR 0.81, 95% CI 0.68-0.96; I2 = 32%), but not urinalysis (RR 0.91, 95% CI 0.78-w1.07; I2 = 20%). Time in the emergency department was not changed. Fewer non-randomized studies reported these outcomes, with some findings reversed or attenuated (fewer antibiotic prescriptions and less urinalysis in tested patients).

Conclusions: Point-of-care testing for influenza influences prescribing and testing decisions, particularly for children in emergency departments. Observational evidence shows challenges for real-world implementation.

Keywords: diagnostics; influenza.

Figure 1.

PRISMA flowchart of included and excluded papers. Abbreviations: POCTs, point-of-care tests; PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses; RCT, randomized, controlled trials.

Figure 2.

Risk of bias summary for included studies.

Figure 3.

Antibiotic prescribing. Abbreviations: CI, confidence interval; POCT, point-of-care test; RCT, randomized, controlled trial.

Figure 4.

Routine bloods or full blood count. Forest plot of meta-analyses of randomized and observational studies reporting full blood counts or routine bloods comparing POCT vs usual care. Abbreviations: CI, confidence interval; POCT, point-of-care test; RCT, randomized, controlled trial.

Figure 5.

Chest radiography. Forest plot of meta-analyses of randomized and observational studies reporting chest radiography comparing POCT vs usual care. Abbreviations: CI, confidence interval; POCT, point-of-care test; RCT, randomized, controlled trial.