Predictors of positive temporal artery biopsy in patients with giant cell arteritis and polymyalgia rheumatica (comment on the article by Marí et al.).
We read with interest the article of Soultati et al., concerning the burden of incidental findings in clinical practice encountered in a tertiary care center. Interestingly, the author reported that 28.8% patients had incidental findings detected with traditional imaging techniques (i.e., radiography, endoscopy, ultrasonography, computed tomography) . Although this is noteworthy, incidental findings identified while performing routine laboratory testing might be as prevalent as those encountered with radiological procedures. The confrontation with unexpected laboratory data (laboratory “incidentalomas”) is commonplace due to the huge number of routine tests (often inappropriate) that clinical laboratories perform everyday. Globally, the prevalence of laboratory incidental findings might be as high as 10%. In a very large study issued by in the Swiss Army, the most frequent pathologies detected by voluntary laboratory testing were low hemoglobin levels (iron deficiency anemia, 16.8%), elevated levels of alanine aminotransferase (liver disease or alcohol abuse, 9.8%), creatinine (renal insufficiency, 1.8%), thrombocytosis (1.5%), glucose (impaired glucose tolerance, 0.4%), ferritin (iron overload/ haemochromatosis, 0.1%) and eosinophilia (2.6%) . Monoclonal gammopathy of undetermined significance are also very frequent in the elderly, with a global prevalence of 3.0 to 5.0%, increasing to 5.3% among persons 70 years of age or older and 7.5% among those 85 years of age or older. The origin of these laboratory “incidentalomas” is multifaceted. Other than existing pathologies, they can be due to laboratory errors, or simply define “healthy outliers” since the usual approach for interpreting laboratory results is the comparison with ranges derived from a “reference” population that – by definition – represent only 95% of reference subjects . Nevertheless, the high prevalence of laboratory incidental findings deserves scrutiny for troubleshooting the cause, especially when they cannot be related to underlying pathologies. As such, patients might be subjected to further risks such as unnecessary (invasive) diagnostic procedures and inappropriate treatment.