White blood cell counts, CRP, GGT and LDH in the elderly German population

Background Hematological abnormalities are frequently found in geriatric patients. However, little data is available on reference values for total blood cell counts in older patients. This study is focused on the analysis of reference values for white blood cell counts in aged persons ≥60 years. Methods This was a cross-sectional study of outpatient laboratory data of 2015 from a German countrywide working laboratory company; inclusion criteria: age ≥60 years, parameters evaluated by the laboratory company between 1.1.2015 and 31.12.2015; exclusion criteria: glomerular filtration rate (GFR) <60 mL/min, lack of inclusion criteria; primary objective: mean leukocyte count; secondary objective: mean counts of lymphocytes, eosinophil, neutrophil and basophil leukocytes as well as platelets, C-reactive protein (CRP), γ-glutamyl transferase (GGT) and lactate dehydrogenase (LDH) in hematologically healthy persons aged ≥60 years. Results Data of 30,611 persons aged ≥60 years were evaluated by age groups. Results for leukocytes, basophils, eosinophils, neutrophils and lymphocytes remained within the reference ranges recommended by the German Society of Hematology and Oncology (DGHO) and the German Association of Specialists in Internal Medicine (BDI); the lower reference limit for normal platelet values in males was below the DGHO reference value with 136,000/μL (confidence interval [CI] 129,000;142,000); similarly, our results for normal monocyte values were above the DGHO reference values with 6.0% (5.7;6.2) to 14.3% (13.9;14.8) in males and 5.4% (5.2;5.6) to 12.9% (12.6;13.4) in females; CRP, GGT and LDH values were above the BDI reference values, comparable with the previous data of a senior patient cohort analysis. Conclusions Adaptation of reference values for selected laboratory parameters in older German patients should be well considered.