A system for determining an assessed carbohydrate-to-insulin ratio (CIR new) of a patient, comprising: a memory component adapted for storing an initial set of values comprising at least a normoglycemia glucose level (BG 0), a target glucose level, an insulin sensitivity, and an estimated carbohydrate-to-insulin ratio (CIR old); a bolus selection component adapted for selecting a test bolus corresponding to the stored initial set of values and a planned meal; a user interface component adapted for selecting a meal of a known content of known carbohydrate load (Carbs); a glucose sensing component adapted for periodically determining a post-prandial glucose level of the patient subsequent to administration of the test bolus and consumption of the planned meal; and a CIR assessment component adapted for determining the assessed carbohydrate-to-insulin ratio (CIR new) of the patient based on the initial set of values and the post-prandial glucose level value, wherein the determination of the post-prandial glucose level is repeated until: either a substantially constant glucose level (BG 1) is achieved, in which case the assessed carbohydrate-to-insulin ratio (CIR new) is calculated as: CIR New = CIR Old * Carb carb + CIR Old * CBG − TBG IS when the difference (ΔBG) between BG 1 and BG 0 is larger than a predefined value and CIR new = Carb carb CIR old − Δ BG IS when the difference (ΔBG) between BG 1 and BG 0 is smaller than the predefined value; or a normal post-prandial glucose level is achieved, in which case the assessed carbohydrate-to-insulin ratio (CIR new) is calculated as: CIR new = CIR old ⋅ ∏ i = 1 n Carbs + CG i ∏ i = 1 n Carbs + CB i ⋅ CIR old where n = number of periods used for determining the assessed carbohydrate-to-insulin ratio (CIR new) i = a counter designating each period CB i = a correction bolus needed when CBG is above TBG CG i = a glucose correction needed when CBG is below TBG a memory component adapted for storing an initial set of values comprising at least a normoglycemia glucose level (BG 0), a target glucose level, an insulin sensitivity, and an estimated carbohydrate-to-insulin ratio (CIR old); a bolus selection component adapted for selecting a test bolus corresponding to the stored initial set of values and a planned meal; a user interface component adapted for selecting a meal of a known content of known carbohydrate load (Carbs); a glucose sensing component adapted for periodically determining a post-prandial glucose level of the patient subsequent to administration of the test bolus and consumption of the planned meal; and a CIR assessment component adapted for determining the assessed carbohydrate-to-insulin ratio (CIR new) of the patient based on the initial set of values and the post-prandial glucose level value, wherein the determination of the post-prandial glucose level is repeated until: either a substantially constant glucose level (BG 1) is achieved, in which case the assessed carbohydrate-to-insulin ratio (CIR new) is calculated as: CIR New = CIR Old * Carb carb + CIR Old * CBG − TBG IS when the difference (ΔBG) between BG 1 and BG 0 is larger than a predefined value and CIR new = Carb carb CIR old − Δ BG IS when the difference (ΔBG) between BG 1 and BG 0 is smaller than the predefined value; or a normal post-prandial glucose level is achieved, in which case the assessed carbohydrate-to-insulin ratio (CIR new) is calculated as: CIR new = CIR old ⋅ ∏ i = 1 n Carbs + CG i ∏ i = 1 n Carbs + CB i ⋅ CIR old where n = number of periods used for determining the assessed carbohydrate-to-insulin ratio (CIR new) i = a counter designating each period CB i = a correction bolus needed when CBG is above TBG CG i = a glucose correction needed when CBG is below TBG either a substantially constant glucose level (BG 1) is achieved, in which case the assessed carbohydrate-to-insulin ratio (CIR new) is calculated as: CIR New = CIR Old * Carb carb + CIR Old * CBG − TBG IS when the difference (ΔBG) between BG 1 and BG 0 is larger than a predefined value and CIR new = Carb carb CIR old − Δ BG IS when the difference (ΔBG) between BG 1 and BG 0 is smaller than the predefined value; or a normal post-prandial glucose level is achieved, in which case the assessed carbohydrate-to-insulin ratio (CIR new) is calculated as: CIR new = CIR old ⋅ ∏ i = 1 n Carbs + CG i ∏ i = 1 n Carbs + CB i ⋅ CIR old where n = number of periods used for determining the assessed carbohydrate-to-insulin ratio (CIR new) i = a counter designating each period CB i = a correction bolus needed when CBG is above TBG CG i = a glucose correction needed when CBG is below TBG where n = number of periods used for determining the assessed carbohydrate-to-insulin ratio (CIR new) i = a counter designating each period CB i = a correction bolus needed when CBG is above TBG CG i = a glucose correction needed when CBG is below TBG