Dear sir, my mother is a diabetes patient, i want purchase a good suger testing machine which is having good accuracy. ?

Great!!!: That is so wonderful to want that for your mom! her insurance however will decide for her what machine she will use because the expensive part are the test strips. Her doctor might even be able to get the machine for free, or a diabetic instructor . Just start asking them. They are all accurate, some just easier to use than others

Easily done: All the machines sold in usa have to conform to fda regulations on devices and be accurate (compared to concurrent venous sugar test) to within about 15% , higher or lower, of 'real' number.. So if it says 'fda approved' you can trust it. The new continuous glucose monitor by dexcom, often recommended for patients on 4 shots of Insulin or an Insulin pump, has now reached same level of accuracy.