Okla. Admin. Code § 252:301-7-17
A laboratory may elect to participate in PT studies more frequently than required by the semiannual schedule. Additional studies are not distinguished from the routinely scheduled studies. They are counted and scored the same way and must be at least seven (7) calendar days apart.
Added at 25 Ok Reg 2247, eff 7-11-08
Amended at 39 Ok Reg 1063, eff 9-15-22