User Performance Evaluation of Contour® Plus One, Accu-Chek® Performa Connect, FreeStyle Optium Neo and OneTouch® Select Plus Blood Glucose Monitoring Systems Following ISO 15197:2013; EN ISO 15197:2015

Study start date: September 1, 2016

Inclusion Criteria: * Male or female, with type 1 diabetes, type 2 diabetes or subjects without diabetes * Signed informed consent form * Minimum age of 18 years * Subjects are legally competent and capable to understand character, meaning and consequences of the study. * If blood glucose values \< 80 mg/dl or \> 300 mg/dl shall be measured after short term alteration in insulin therapy: * Male or female with type 1 diabetes and intensified insulin therapy or insulin pump therapy. * Signature of subjects to document consent with these procedures on informed consent form. Exclusion Criteria: * Pregnancy or lactation period * Severe acute disease (at the study physician's discretion) * Severe chronic disease with potential risk during the test procedures (at the study physician's discretion) * Current constitution that compromises the subject's capability to participate in the study (at the study physician's discretion) * Being unable to give informed consent * \< 18 years * Legally incompetent * Being committed to an institution (e.g. psychiatric clinic) * Language barriers potentially compromising an adequate compliance with study procedures * Dependent on investigator or sponsor * If blood glucose values \< 80 mg/dl shall be measured after short term alteration in insulin therapy, subjects with type 1 diabetes, suffering from: * Coronary heart disease * Condition after myocardial infarction * Condition after cerebral events * Peripheral arterial occlusive disease * Hypoglycemia unawareness Inclusion and exclusion criteria defined by ISO 15197:2013; EN ISO 15197:2015: * Only subjects with diabetes type 1 or type 2 will be included. * Demographic data will be collected to demonstrate that subjects represent different ages, genders and education levels. * In deviation from ISO 15197:2013; EN ISO 15197:2015, included subjects may have participated in a study involving the BGMS, but must not yet have performed measurements with the BGMS according to their own statement for the last 3 years. * In addtition, included subjects did not use the BGMS being evaluated at home for the last 3 years according to their own statement. * In order to ensure that capillary blood samples meet the requirements indicated in the manufacturer's labelling, * a physician will review the subjects' anamnesis and medication and check for interfering substances indicated in the manufacturer's labelling. * the hematocrit value of each subject will be checked to be within the range indicated in the manufacturer's labelling (hematocrit determination before or after the measurement procedure).