49 CFR §40.155

1. (a)When the laboratory reports that a specimen is dilute, you must, as the MRO, report to the DER that the specimen, in addition to being negative or positive, is dilute.
2. (b)You must check the “dilute” box (Step 6) on Copy 2 of the CCF.
3. (c)When you report a dilute specimen to the DER, you must explain to the DER the employer's obligations and choices under § 40.197, to include the requirement for an immediate recollection under direct observation if the creatinine concentration of a negative-dilute specimen was greater than or equal to 2mg/dL but less than or equal to 5mg/dL.
4. (d)If the employee's recollection under direct observation, in paragraph (c) of this section, results in another negative-dilute, as the MRO, you must:
   1. (1)Review the CCF to ensure that there is documentation that the recollection was directly observed.
   2. (2)If the CCF documentation shows that the recollection was directly observed as required, report this result to the DER as a negative-dilute result.
   3. (3)If CCF documentation indicates that the recollection was not directly observed as required, do not report a result but again explain to the DER that there must be an immediate recollection under direct observation.