Diagnostic Value of Serum Urokinase-Type Plasminogen Activator Receptor in Children With Acute Appendicitis

Acute appendicitis (AA) is the most common surgical emergency in children. The accurate and timely diagnosis of AA in children can be challenging, and delayed diagnosis rates have been reported to range from 5.9% to 27.6%. Although combining clinical history and repeated physical examination with laboratory tests and radiographic imaging modalities help reach the diagnosis, novel biomarkers can support the surgeons' decision as well. The aims of this study were to evaluate a new plasma marker, urokinase-type plasminogen activator receptor (uPAR), to improve diagnostic accuracy in AA patients, and to determine a cutoff value of uPAR, which can safely include/exclude the diagnosis of AA.

We conducted a prospective study of children who underwent surgery for AA. Patients were categorized into the following 3 groups: group 1, controls consisted of 32 healthy volunteers; group 2, patients underwent surgery for nonperforated AA (n = 35); and group 3, patients underwent surgery for perforated AA (n = 21). Blood was sampled from group 1 at the admission and from group 2 and 3 before appendectomy. Serum uPAR, white blood cell count, absolute neutrophil count (ANC), and C-reactive protein concentrations were measured.

Urokinase-type plasminogen activator receptor, ANC, and white blood cell count values were significantly higher in group 2 and 3 than group 1, but there was no significant difference between group 2 and 3. C-reactive protein values were significantly higher only in group 3 than other groups. The cutoff value for uPAR is 2.2 ng/mL with sensitivity of 85.7% and specificity of 84.3% and ANC is 5900 cells/mm with sensitivity of 91.1% and specificity of 96.9% to diagnose appendicitis. The specificity was 81.3% and sensitivity was raised to 98.2% when evaluated together.

The incorporation of uPAR count and ANC could be a strong predictor of AA in children.