The error standard of the blood glucose meter is related to the measured blood glucose concentration, and the permissible error standard will be different for different measured blood glucose concentrations. When the blood glucose concentration is <5.5mmol/L, the error between venous blood glucose and fingertip blood glucose generally does not exceed 0.83mmol/L; when the blood glucose concentration is ≥5.5mmol/L, the deviation between venous blood glucose and fingertip blood glucose generally does not exceed 15%. Blood glucose meters usually require the use of enzymes on test strips to react with glucose in the blood, which is then converted into an electronic signal to produce the result. During this period, neither the external environment, the state of the enzyme, nor the conversion of the instrument is controllable, so the test results are prone to errors. Therefore, you should try to buy a regular blood glucose meter and follow the steps strictly when measuring blood glucose so as not to affect the test results. If the blood glucose meter has a relatively large error, it should be corrected or replaced in time. Consult your physician for specific checking methods.