“Caveats are that it requires lab testing, so children who do not have lab studies performed will not be included,” she noted. “It also needs sophisticated calculations, which may be a barrier, but can be easily programmed into an electronic system.”

“At present, the guideline for evaluating a child with appendicitis is based on clinical judgment and experience,” she said. “This calculator provides an objective measurement of risk, and thus may be applied and/or integrated into clinical practice, with an understanding of its limitations.”

Dr. Ethan Wiener, associate chief in the Division of Pediatric Emergency Medicine at Hassenfeld Children’s Hospital at NYU Langone Health in New York City, said, “Coming from authors who have done a great deal of the important appendicitis work in the last decade, this paper is an effort to develop a better clinical prediction rule for appendicitis.”

“The real question with this rule is applicability,” he told Reuters Health by email. “The lowest-risk groups identified, [with] <5 percent and 5 percent–15 percent risk, have somewhere between a 1 in 10 to 1 in 20 risk of appendicitis.”

Most clinicians would still want to pursue a diagnosis at those levels of risk, he said, given the “significant implications and potential for complications.”

Dr. Wiener added that in his experience, equivocal ultrasounds do not necessarily lead to more CT scans. “Having a patient in the ED undergoing a workup gives us an opportunity to re-examine him or her,” he said. Longer observation may occur in some cases, possibly leading to another ultrasound or surgery or, he acknowledged, a CT scan if indicated.

“It seems like we must continue to rely on the age-old and time-tested physical exam findings of right lower-quadrant pain and associated peritoneal findings to guide clinical impressions and subsequent determination of need for diagnostic work-up,” he concluded.

Dr. S. Daniel Ganjian of Providence Saint John’s Health Center in Santa Monica, California, added, “This study was performed only on patients presenting to a children’s hospital.”

“Validation studies need to be performed to see if this tool can be used on patients who present to the pediatrician’s office or general ED, as opposed to specifically a pediatrics ED,” he said by email.