According to the CGMPs, each manifold filling sequence, each uninterrupted filling sequence, each cryogenic vessel filled and each storage tank following a delivery is considered a new lot and is required to be assigned a new lot number.

The assigning of a single lot number for an entire day production is not acceptable, you must do so by batch. A manufacturing operation, such as the filling of high pressure cylinders on a multi-outlet manifold, is governed by a set of manufacturing procedures or conditions. When the procedures are performed from the beginning to the end of a process they provide assurance that the batch is uniform and consistent. Therefore, each batch is a separate entity with its filling operations unique to that filling sequence.

For firms filling liquid oxygen for delivery to home patients, each of the large cryogenic vessels or dewars (either portable or permanently mounted in a van or a truck) are required to be assigned a unique lot number.
 

At the present time, cryogenic home vessels filled at a patient’s home, i.e., curbside are not required to bear a lot number. However, cryogenic home vessels filled on site and stored for future delivery, or cryogenic home vessels filled by a third party, require lot numbers.