Point-of-Care Testing Shows Promise in Future, Concerns About Sensitivity Accuracy

In a review, investigators summarized the regulatory landscape of point-of-care (POC) testing for viral infections in the United States, addressing important considerations such as site certification, training, and inspection readiness. The review was published in the Journal of Clinical Virology.

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Physicians typically diagnose viral infections using a combination of laboratory-based methods, which included culture, serology, antigen-based tests, and molecular assays in the form of polymerase chain reaction (PCR) tests. The study authors said that even though these methods have provided accurate ways to detect viral pathogens, testing delays in centralized labs could impact patient diagnosis and management.

Due to delays in laboratory uses and because of the COVID-19 pandemic, POC testing, which includes both antigen and molecular assays, gives patents timely diagnosis of serious viral infections, which can include influenza, respiratory syncytial virus, and COVID-19.

Because of the pandemic, there are now “over 250 molecular tests and 50 antigen tests that have been granted [emergency use authorizations,] with 21 molecular and 45 antigen tests authorized for POC testing in a waived setting,” the study authors wrote in.

Diagnosing patients in a timely matter can help inform the appropriate use of antibiotics as well as isolation precautions and other procedures. Rapid POC testing may play a significant role in diagnosing illness because results can be determined in 30 minutes or less. It can also help to improve patient access and play a vital role for areas with limited resources in which lab testing is impractical, and for individuals who may not return to follow-up visits, according to the study.

Additionally, POC tests are often more affordable than laboratory testing, which is more cost-effective for patients. Investigators added that POC tests generally are high in specificity, but false-positive results are possible if the disease prevalence is low.

However, there are issues to consider before their routine use, which can include test performance and specific regulatory requirements, according to the investigators.

Antigen tests are expected to have a sensitivity at 80% or above. Investigators stated “while there are no minimum specificity requirements, most antigen tests are expected to have a specificity of” 90% or greater.

For nucleic acid amplification tests, sensitivity should be 90% or greater and 95% or greater, respectively. Investigators said that the CDC has recommended that a follow-up nucleic acid amplification test be used for patients clinically suspected to have influenza, despite a negative POC test.

However, there has been interest in the development of a POC nucleic acid amplification test, which have been given waived status by the FDA, according to the investigators. They would include high sensitivity of 95% or more and fast turnaround times of under 60 minutes.

One concern of the nucleic acid amplification test is the potential for contamination and false-positive results. Multiplex testing has been offered, which was previously limited to laboratory-based testing. Investigators added that this could provide an advantage for POC settings in collecting a single specimen for multiple pathogen tests.

Investigators did not include at-home antigen and molecular tests in the POC testing scope of the review. POC included near-patient or laboratory-based antigen- and molecular-based testing.

Reference

Shirley JD, Bennett SA, Binnicker MJ. Current regulatory landscape for viral point-of-care testing in the United States. J Clin Virol. 2023;164:105492. doi:10.1016/j.jcv.2023.105492