Clinical and Laboratory Standards Institute document M40-A2—Quality Control of Microbiological Transport Systems; Approved Standard—Second Edition presents the criteria that shall be considered when choosing a microbiological transport device to facilitate sample preservation. QC considerations for the manufacturer and testing laboratory are presented, as well as techniques, control microorganisms, and acceptability criteria. This document provides a consistent protocol for initial testing of microbiological transport devices by manufacturers and a method by which laboratories can validate manufacturer claims and compare devices.

The transport of clinical specimens is a critical component for accurate diagnosis. Preservation of inherent, interpretive attributes of microorganisms and/or nucleic acids can be quickly compromised when the transport conditions or transport devices are suboptimal. The advent of antigen detection methods, methods for amplification and detection of genetic elements, and the requirement for local or distant transport of these specimens to a testing facility has imposed further considerations on manufacturers to provide products that will not compromise reporting of clinically relevant laboratory data to physicians. Clinicians should be able to collect and submit specimens to the laboratory and laboratorians should be able to retrieve specimens from containers, devices, and transport media with a reasonable assurance that the viability of microorganisms and/or preservation of nucleic acids present in the specimen will be maintained.

This standard provides criteria to the manufacturers and end users of transport devices to assist in providing and choosing dependable products for the transport of microbiological clinical specimens. Manufacturers will be able to state whether or not the performance characteristics for specific groups of microorganisms and transport devices of a particular product satisfy the performance standards as specified in this document. Furthermore, manufacturers shall state whether or not any additional testing is required before the use of a particular product.

Secondary distributors and end users must assume the responsibility for storage and transport conditions of specimen collection devices before and after use, by adhering to the conditions specified by the manufacturer or those deemed optimum by the laboratory in order to ensure microorganism viability/stability.

In this document, except as specifically noted, QC consists of an assessment of the performance characteristics of a complete device, and not the individual components. There are multiple variables involved in the manufacture of a transport device, including, but not limited to, the container, transport medium, collection device, packaging, and environment. It is fundamental that the assessment of the device be based on measurable performance characteristics for the particular device.

This document is not intended to provide proprietary information on product development, but rather to provide assurance to the device’s user that manufacturer claims are met following standardized testing and acceptance criteria. It provides guidance to the manufacturer in addressing critical issues related to specimen integrity specific to the type of testing to be performed, eg, bacterial and viral culture, or nucleic acid detection. This document does not address the technique of transport device manufacturing, but focuses on the methods for QC testing and acceptance criteria in order to provide a product suitable for the analysis of clinical specimens for agents of disease.

Transport devices are essential components of the preexamination process of microbiology laboratory testing. It is recognized that these early steps in the total testing process are critical to the production of clinically relevant information. Patients, physicians, health care providers, and laboratorians expect products that meet the highest standards of laboratory practice. This document will facilitate this goal.a And while it is beyond the scope of this document to address the design of devices, it is imperative that device design promotes correct use, and that laboratorians select devices that best serve the needs of the physician and the patient.

Although a discussion of specimen transport conditions is beyond the scope of this document, it is recognized that temperature has a significant effect on the preservation of microorganisms in various transport devices. A number of recent studies12,20 have compared performance of transport devices inoculated with various organisms at controlled room temperature (20 to 25°C) and cold temperature (2 to 8°C). These studies have established that simulated transport performance at cold temperature yields superior results compared to transport at room temperature. These data support the suggestion that the current recommendations of room temperature transport do not represent the optimal holding temperature for maximum preservation of microbiological samples.9-11,21-27 If transport conditions of the end user differ from those validated by the manufacturer, actual transport conditions should be tested in order to determine viability and overgrowth of microorganisms (eg, in insulated coolers with cold packs).

Manufacturers are encouraged to perform QC of microbial transport devices at both controlled room temperature and cold temperature as defined in Section 4.2 and, furthermore, to specify this practice in their package inserts and regulatory submissions. Inclusion of this information will permit users who wish to transport specimens for testing by their laboratories at cold temperature reasonable assurance that manufacturers performed testing at the temperature used by their laboratories. If further investigations lead to changes in the current recommendations for controlled room temperature specimen transport, manufacturers performing QC at both temperatures would not have to make any subsequent changes in their QC procedures or package inserts. Finally, to emphasize that few standards for QC have been suggested for many microbiology transport devices, some of the protocols provided are general outlines designed, in part, to promote discussion among the manufacturers, laboratories, and users regarding what would constitute an appropriate standard, as well as promote research and publication that may serve as the foundation of new standards as activity in this area moves forward.