You can find more information concerning split specimens in several sections of this part:
§ 40.3 - Definition.
§ 40.65 - Quantity of split specimen.
§ 40.67 - Directly observed test when split specimen is unavailable.
§§ 40.71-40.73 - Collection process for split specimens.
§ 40.83 - Laboratory accessioning of split specimens.
§ 40.99 - Laboratory retention of split specimens.
§ 40.153 - MRO notice to employees on tests of split specimen.
§§ 40.193 and 40.201 - MRO actions on insufficient or unavailable split specimens.
Appendix D to Part 40 - Report format for split specimen failure to reconfirm.
[65 FR 79526, Dec. 19, 2000, as amended at 82 FR 52245, Nov. 13, 2017]