Blood loss can be measured directly and indirectly. The latter reflects blood loss through the assessment of hemoglobin level. Thus aim of this study was to determine the applicability of the drop in hemoglobin levels blood loss calculation when transfused blood volume is taken into account on the patients who underwent aneurysmectomy and to estimate whether this model is applicable on geriatric population. In this study, 14 patients were included and their blood loss was calculated based on hemoglobin concentration. Linear correlation (y = 0.18467 + 1.19315·x) with high correlation coefficient (r = 0.90809) was found between calculated and collected blood loss only if transfused blood volume was taken into account. The coefficient of the regression slope for the blood volume measured during surgery and the calculated blood loss in eight patients ≤65 years (y = 0.90866 + 0.86296·x) and six patients >65 years (y = 0.0299 + 1.32707·x) did not show any significant difference. The applicability of the indirect measurement of surgical blood loss, when transfused blood volume was taken into account, was demonstrated in both populations, in the age of 65 and less and in the age over 65 years after aneurysmectomy.