Monitoring surface chemical contaminations in the chemotherapy control laboratory

Introduction
Analytical control for unit release on line of extemporaneous cytotoxic preparations serves as a means to ensure the medication circuit in the hospital is made safe. Sampling is needed for the control and handling the sample outside the isolator constitutes a potential source of exposure for the staff. The goal of the present work is to evaluate surface chemical contamination associated with the analytical control circuit for such preparations.

Equipment and methods
The samples of cytotoxics are taken using vials in a vacuum and routed to the laboratory by pneumatic conveying system. They are placed on an auto-sampler before being analysed by injection into the flow or CLHP. Within the control laboratory, a cytotoxic control area was defined. 25 critical surfaces (in the handling zone and outside it) had samples taken by wet swabbing. Platinum is an element found in carboplatin, cisplatin and oxaliplatin: it is used as a sensitive and specific marker for contamination (detection limit of 2 ng) and is representative of the control activity (31% of cytotoxic controls).

Results
No contamination was found outside the handling area. Within the handling area, the floors and work surfaces, reception, storage and elimination zones were not contaminated. Just 6 of the 22 surfaces sampled in this zone were affected: these correspond to the transfer cartridges (1 result <LD on 2 samples), the automatic dispensing pipetters (<LD and 19 ng) on the CLHP carousels (26, 46 and 109 ng).

Conclusion
The space for handling of cytotoxics and control tools inside a laboratory must be clearly defined as being reserved for that activity. Handling within this zone must be accompanied by wearing of personal protective equipment and protocols for decontamination of surfaces.