Use of plastic tubes for collection of patient samples as well as for testing (ABO/Rh determination, unexpected antibody detection and identification, and crossmatching)

A medical technologist at a hospital in Louisiana reports that as a safety precaution all patient specimens (including those intended for blood bank testing) are drawn into plastic tubes. In addition, their clinical laboratory performs the actual testing using either the original collection tube or plastic aliquot tubes. However, their blood bank still performs serologic testing (i.e. type and screen, panel workups, crossmatches, etc) in glass test tubes (even though the blood bank specimen is collected in a plastic tube). Their blood bank has been asked to perform their blood bank testing in plastic test tubes. The Louisiana technologist wants to know if other blood bank colleagues are using plastic test tubes for their serologic testing. She is aware of the earlier forum discussion on plastic tubes but states that information focuses mainly on specimen collection tubes and not on the actual tube used in the testing procedures.

Editor's note: At the Kenneth Norris Cancer Hospital blood bank (where he is transfusion service medical director), plastic tubes are used for collecting patient samples, a Gel-system is used for antibody screening, antibody identification and antiglobulin crossmatching, but glass test tubes are used when performing ABO/Rh testing and immediate spin crossmatches. The possibility of switching to plastic test tubes for the aforementioned testing is under discussion. If this should this occur, an appropriate validation would be done before implementing the switch for tests of record.

REACTIVATED Sept. 29, 2003

A transfusion medicine physician in New York would like to continue the discussion regarding the use of plastic tubes when performing the analytic steps of manual tube agglutination procedures such as ABO/Rh and antibody detection testing. Many hospitals collect patient samples for blood bank testing into plastic tubes, but continue to perform the analytic testing (ABO/Rh and antibody detection testing) in secondary tubes that are made of glass. The New York physician wants to know if any blood bank has validated the use of plastic tubes for these analytic procedures, and if so what was the validation strategy. The New York physician states that "regulatory agencies" are pressuring his hospital to use plastic "when possible". This includes not only using plastic tubes for collecting samples at the time of phlebotomy but for performing the analytic procedures that are done on aliquots that are taken from the original specimen tubes. So far his hospital's position has been that no blood banks in their local community have found plastic tubes to be satisfactory during the analytic testing procedures. He has heard an opinion that agglutinates "behave" somewhat differently in plastic, and that the shake "feels" different to experienced technologists. He would like to know if there are any blood banks that have tried using plastic tubes for agglutination? If so, what has been the experience in terms of validating the use of plastic tubes and satisfaction with their use during analytic procedures? Have other blood banks come under pressure from regulatory bodies to switch from glass to plastic tubes for the analysis of ABO/Rh and antibody detection testing?

The following response has been received.

ADDENDA Sept. 30, 2003

1. A surveyor in California with regulatory oversight and 25 years experience in laboratory management reports that he knows of no requirement for the use of plastic as a "safer" material. He writes (verbatim) "I have read documents from Cal-OSHA reversing recommendations for using plastic over glass. I would strongly urge those who wish to switch from glass to plastic to consider supplier qualification as an issue, especially if the blood bank laboratory does not directly control purchasing. There have been numerous instances of extreme lot-to-lot variation in tube-bottom configuration, and resulting inconsistencies with interpretation. I believe that a common sense approach is appropriate, if a product can be obtained, consistently, and works in the hands of those using it consistently (validation), use it."

ADDENDA Oct. 1, 2003

2. A blood bank technologist in Southern California reports that her laboratory has an outreach program and that CAL-OSHA has cited several of their physician clients for not collecting specimens in 'safer' plastic tubes. It is because their clients were being given citations that the responding colleague's laboratory did validation studies that showed it to be acceptable to collect specimens in plastic tubes and then run the majority of their analyses on those specimens, including Blood Bank testing. However, she adds that unlike their experience with specimen collection tubes, (which are now mostly plastic), her laboratory is still using glass tubes for the actual ABO/Rh and antibody detection testing, and that they have not had any pressure to change their blood bank testing materials from glass to plastic tubes. She also adds that they will probably not even think about switching to plastic for the analytic steps until they get heavy pressure. Finally, she comments that they are working on implementing the GEL system for antibody screening and identification testing and once that system is in place, it will decrease the use of glass testing tubes, but it certainly will not eliminate their use entirely.

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Ira A. Shulman, MD
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W. Tait Stevens, MD
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