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Use of plastic tubes for tube testing


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I am being told we need to switch to using plastic 12x75mm tubes instead of the glass 10x75mm tubes because the glass is a safety risk.  I have never in 25 years as a MT used anything but glass for tube testing.  At a minimum for doing DATs and LISS tube antibody screens.  I tried it yesterday but I can't get a good button, a positive reaction with polyspecific AHG+IgG check cells, and it seems like the cells are getting stuck on the side and bottom of the tube.  Does any use plastic tubes for completing tube testing on patient samples?  If so can you please help me with a validation?

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When I first started out in the profession (about the same time as Karl Landsteiner, or so my old bones tell me), we originally did indirect and direct antiglobulin tests (IAT and DAT) on opaque white tiles, and then moved on to using plastic tubes for the spin IAT and DAT.  In those days, there was no doubt that the 75x12mm tubes were made of fairly thick plastic.  It was then discovered that immunoglobulins, being proteins, would "adhere" to the sides of these tubes in preference to sensitising some red cells with weaker expression of certain antigens, and so weak antibodies may well have been missed (and vice versa, some weak antigens, particularly some of the D antigens could be missed).
As a result, we were advised to go over to glass 75x12mm tubes (except in Dr Jan Ikin's [or EWI's] laboratory, where glass precipitin tubes were used (a real pain, as they were about 40mm in length and about 6mm in diameter - so very little volume, and the tests had to be washed by hand for a minimum of six times).  This was all okay unless you plunged your hand into a bulk supply of the 12x75mm glass tubes and found some of them had shattered (usually by finding the shards buried in your hand, and with blood dripping everywhere).  As a result, the Health and Safety Police told us that we should switch back to plastic, but a different plastic, which had some form of coating on it that meant that proteins did not bind to this particular kind of plastic in the same way, and I must admit that there was very little difference in terms of agglutination strength between the two.  HOWEVER, if you came across split tubes in the bulk supply, it was like being cut by a serrated edge, such as a bread knife, rather than a smooth edge, such as a carving knife.  It used to hurt like Hell and took a month of Sundays to heal!

I would, therefore, thoroughly recommend that you either switch to either liquid or solid phase microtitre plates, or, better still, column agglutination technology, both of which will not only be safer for the operatives, but will also improve your sensitivity, without sacrificing too much in the way of specificity.

JUST MY PERSONAL OPINION.

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10 minutes ago, Malcolm Needs said:

When I first started out in the profession (about the same time as Karl Landsteiner, or so my old bones tell me), we originally did indirect and direct antiglobulin tests (IAT and DAT) on opaque white tiles, and then moved on to using plastic tubes for the spin IAT and DAT.  In those days, there was no doubt that the 75x12mm tubes were made of fairly thick plastic.  It was then discovered that immunoglobulins, being proteins, would "adhere" to the sides of these tubes in preference to sensitising some red cells with weaker expression of certain antigens, and so weak antibodies may well have been missed (and vice versa, some weak antigens, particularly some of the D antigens could be missed).
As a result, we were advised to go over to glass 75x12mm tubes (except in Dr Jan Ikin's [or EWI's] laboratory, where glass precipitin tubes were used (a real pain, as they were about 40mm in length and about 6mm in diameter - so very little volume, and the tests had to be washed by hand for a minimum of six times).  This was all okay unless you plunged your hand into a bulk supply of the 12x75mm glass tubes and found some of them had shattered (usually by finding the shards buried in your hand, and with blood dripping everywhere).  As a result, the Health and Safety Police told us that we should switch back to plastic, but a different plastic, which had some form of coating on it that meant that proteins did not bind to this particular kind of plastic in the same way, and I must admit that there was very little difference in terms of agglutination strength between the two.  HOWEVER, if you came across split tubes in the bulk supply, it was like being cut by a serrated edge, such as a bread knife, rather than a smooth edge, such as a carving knife.  It used to hurt like Hell and took a month of Sundays to heal!

I would, therefore, thoroughly recommend that you either switch to either liquid or solid phase microtitre plates, or, better still, column agglutination technology, both of which will not only be safer for the operatives, but will also improve your sensitivity, without sacrificing too much in the way of specificity.

JUST MY PERSONAL OPINION.

This information is extremely helpful.  We do use gel for all other testing but we have a fair amount of patients with WAA that we have been recommended by our IRL to use LISS tube antibody screens and crossmatches.  Plus my staff complain about too much pipetting (even though we have the really light ergonomic pipetters).  Also, we don't have an option for completing anti-C3bC3d testing except by tube method.  I did validate the use of polyspecific gel and we already do IgG gel DATs.  I've never used microplates but I'll look into it.  Thanks for the information.

 

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On 3/4/2022 at 1:43 PM, Sonya Martinez said:

I am being told we need to switch to using plastic 12x75mm tubes instead of the glass 10x75mm tubes because the glass is a safety risk.  I have never in 25 years as a MT used anything but glass for tube testing.  At a minimum for doing DATs and LISS tube antibody screens.  I tried it yesterday but I can't get a good button, a positive reaction with polyspecific AHG+IgG check cells, and it seems like the cells are getting stuck on the side and bottom of the tube.  Does any use plastic tubes for completing tube testing on patient samples?  If so can you please help me with a validation?

Who is telling you to switch? Are the plastic tubes transparent enough to see mixed field and weak reactivity clearly?

As far as validating I would guess you could use the centrifuge calibration that determines correct spin times  

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@Sonya Martinez, I also would like to know who it is telling you this. My guess is it is some infection control nurse during an inspection that has no idea about immunology, just following a checklist. I experienced that years ago and simply pointed them to similar information that @Malcolm Needs stated. I have always been taught that plastic tubes were not acceptable in blood bank for that reason.

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9 minutes ago, Sonya Martinez said:

@jayinsat and @Ensis01:  This is coming from our QA Compliance Coordinator and Safety Officer (CLS not a nurse) due to a cut on a staff member's finger from broken glass (contaminated with 1% patient cell suspension in IH LISS).  

OMG!!!!!!!!!!!!!!!!!!!!  So, no scientific background whatsoever.

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14 hours ago, Sonya Martinez said:

@jayinsat and @Ensis01:  This is coming from our QA Compliance Coordinator and Safety Officer (CLS not a nurse) due to a cut on a staff member's finger from broken glass (contaminated with 1% patient cell suspension in IH LISS).  

Ah, inform them that by their logic; phlebotomist's should not use needles due to the many unintended sticks in hospitals each year

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This issue - the switch to plastic - seems to bubble up every few years (pardon the minor pun). When I was a puppy in my early years, last century, labs were already tossing around the idea to avoid potentially dangerous, sharp glass tubes. When broken, the plastic used for test tubes is also sharp, possibly worse that glass, as Malcolm suggests.

As others have mentioned, static is always an issue with the plastic version, rather than occasional with glass. Other than that, and in my experience, plastic test tubes tubes work almost as well as glass for serological testing. However, many "tube reagents" are not formulated for, or qualified in plastic. The Directions for Use/ Package Inserts may be restrictive.

Two points - personal opinion of a cranky old man:

1. One event does not indicate a trend - changing the whole system to address a single cut-finger incident is unreasonable.

2. The various safety apparatuses (however they be mis- or confusingly named) exist to limit institutional legal liability, i.e., prevention of legal action ("please don't sue us"). The workers' actual safety is often secondary.

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5 hours ago, exlimey said:

This issue - the switch to plastic - seems to bubble up every few years (pardon the minor pun). When I was a puppy in my early years, last century, labs were already tossing around the idea to avoid potentially dangerous, sharp glass tubes. When broken, the plastic used for test tubes is also sharp, possibly worse that glass, as Malcolm suggests.

As others have mentioned, static is always an issue with the plastic version, rather than occasional with glass. Other than that, and in my experience, plastic test tubes tubes work almost as well as glass for serological testing. However, many "tube reagents" are not formulated for, or qualified in plastic. The Directions for Use/ Package Inserts may be restrictive.

Two points - personal opinion of a cranky old man:

1. One event does not indicate a trend - changing the whole system to address a single cut-finger incident is unreasonable.

2. The various safety apparatuses (however they be mis- or confusingly named) exist to limit institutional legal liability, i.e., prevention of legal action ("please don't sue us"). The workers' actual safety is often secondary.

I did check our IFU and they did specifically state to use glass tubes.  No more arguments.

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To emphasize Exlimey's point: 

"One event does not indicate a trend - changing the whole system to address a single cut-finger incident is unreasonable". Also of concern is the use of plastic, who knows in the near future if this will be available in test tube form in abundance? We need to look at how and why this accident occurred? Everything in our lives cannot be padded so we don't fall, trip, get our feelings hurt (sorry had to add that), or get a cut. I know it's very serious to get a cut from a blood-contaminated item but I personally would look at what is reasonable and prudent. I know we have 'seasoned' techs on this site, probably 20-30 years in the field that would think it strange for that incident to happen, I would think getting a cut from grabbing "clean" tubes from the dispensary would be more likely because you are grabbing a bunch of tubes but normally you grab tubes with samples in them (contaminated tubes)  from either the centrifuge or tube rack and can clearly see what you are grabbing. 

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