Section 864.8175 - Calibrator for platelet counting(a)Identification. A calibrator for platelet counting is a device that resembles platelets in plasma or whole blood and that is used to set a platelet counting instrument. It is a suspension of particles or cells whose size, shape concentration, and other characteristics have been precisely and accurately determined.(b)Classification. Class II (special controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 864.9 .45 FR 60633, Sept. 12, 1980, as amended at 84 FR 71800 , Dec. 30, 2019