42 CFR §493.1269

1. (a)For manual cell counts performed using a hemocytometer—
   1. (1)One control material must be tested each 8 hours of operation; and
   2. (2)Patient specimens and control materials must be tested in duplicate.
2. (b)For all nonmanual coagulation test systems, the laboratory must include two levels of control material each 8 hours of operation and each time a reagent is changed.
3. (c)For manual coagulation tests—
   1. (1)Each individual performing tests must test two levels of control materials before testing patient samples and each time a reagent is changed; and
   2. (2)Patient specimens and control materials must be tested in duplicate.
4. (d)The laboratory must document all control procedures performed, as specified in this section.