The present invention relates to improved methods of prenatal diagnosis, screening, monitoring andor testing. By setting an angle of grinding traces on an IC chip wafer of chip with a vertical line on side ridges of the IC chip to less than 45 degrees, more preferably 10 to 45 degrees, the chippings including loose chippings can be reduced on the side ridges of the IC chip. Folding handlebars may extend from the base to provide a hand grip for the user.