We assessed the diagnostic accuracy of a newly developed laboratory score-based on CA125, platelet count (PLT), C-reactive protein (CRP), and fibrinogen levels-in the preoperative diagnosis of adnexal mass. In this retrospective single-center study, we analyzed records of 142 patients with 54 malignant (38 %) and 88 benign (62 %) ovarian tumors. Preoperative levels of CA125, PLT, CRP, and fibrinogen were dichotomized according to the common cutoff values (CA125, 35 U/ml; PLT, 350/nl; CRP, 5.0 mg/l; fibrinogen, 400 mg/dl), resulting in "1" for results above the cutoff and "0" for results within the normal ranges. The values (1 or 0) were summarized to a "low" (0-2) or "high" (3-4) score. Its diagnostic accuracy was compared to the "gold standard," CA125. All parameters differed significantly between malignant and benign cases. The score was false positive in 5/88 (5.7 %) and false negative in 13/54 (24 %) of cases. Conversely, CA125 was false positive in 18/88 (20.4 %) and false negative in 4/54 (7.4 %). The diagnostic accuracy of CA125 (>35 U/ml) was sensitivity 0.93, specificity 0.80, positive predictive value (PPV) 0.74, negative predictive value (NPV) 0.95, and positive likelihood ratio (weighted by prevalence) (+LH/p) 2.78. The diagnostic accuracy of the score was sensitivity 0.76, specificity 0.94, PPV 0.89, NPV 0.86, and +LH/p 8.2. In conclusion, the score is easy to use and generates no additional costs. It provides a better specificity, PPV, and +LH/p than CA125. The sensitivity and NPV are lower, but acceptable. A validation of the score in a large patient cohort is needed.
Keywords: C-reactive protein; Diagnosis; Diagnostic accuracy; Fibrinogen; Ovarian cancer; Platelets; Tumor marker.