A late wintertime outbreak of strep throat may sweep through a schoolroom in a matter of days, sending dozens to the doctor. The highly contagious bacteria is spread through airborne particles from coughs and sneezes, as well as infected surfaces.

Every year, some 11 million American children and adults visit the doctor’s office complaining of sore throat and fever, often with swollen lymph nodes and tonsils. Caused by the bacteria streptococcus pyogenes, the illness also brings a fever typically running higher than 101 Fahrenheit (38.3 C), requiring antibiotic treatment.

Yet, researchers say a simple new test—for home and school—may help reduce the annual number of clinical visits for strep throat in the United States by 230,000, in addition to reducing the number of unnecessary antibiotics prescriptions by approximately 8,500.

In a large study, investigators from Boston Children’s Hospital and the University of California, San Diego, analyzed data from nearly 72,000 patients ages 15 and older who’d visited a clinician for strep throat between September 2006 and December 2008. They then developed a diagnostic score by incorporating information about symptoms from patients with local incidences of disease, with which they compared to diagnostic tools traditionally used by doctors.

By using a home diagnostic test, people suffering sore throat might avoid clinical visits—with scores indicating low risk of strep—as well as costly laboratory tests. In the event of illness caused by viral infections, neither testing nor antibiotics would be necessary.

In the study, more than 48,000 patients complaining of sore throat visited a doctor for a test, while approximately half as many used the newly developed home strep test, in trial mode. Interestingly, 24 percent of both groups tested positive for strep, meaning the vast majority presenting at the doctor’s office were suffering from a mere viral infection.

"The model, based on history and recent, local disease patterns without physical examination information, could help clinicians and patients estimate the likelihood of disease before a clinical encounter and help steer these patients to timely, appropriate care when needed,” the researchers wrote in the study, published Tuesday. In some instances, patients unlikely to have [strep] might avoid, or at least delay, an emergency or outpatient visit."

Yet, Robert M. Centor, of the University of Alabama, says the researchers “overestimated the specificity” of the strep test. "Derivation models almost always give better results than validation data sets," he says. "We should use the specificity that they found in their validation data as a more accurate estimate of how this model would work in the future."

Although Centor doubts the home test would offer patients a practical diagnostic for strep throat, he recommended clinicians shave money from the medical bill by prescribing only generic antibiotics for treatment.

 

Source: Fine, Andrew M., Nizet, Victor, Mandl, Kenneth D. A Home Score For Streptococcal Pharyngitis Enabled By Real-Time Biosurveillance: A Cohort Study. Annals Of Internal Medicine. 2013.