Dansket

You didn't say how large your laboratory is and how Transfusion Services is staffed on the night shift. When I was doing manual testing, it was consistent with your new supervisor's approach. An autocontrol was only run with the first panel only. With automated gel testing on ProVue, only full panels can be run. Rule-outs are done by entering panel test results into the AntigenPlus antibody identification software. A maximum of 3 panels would be run before sending specimen to reference lab. This standardized protocol was used in a small hospital transfusion service (<1000 rbcs transfused annually) staffed with generalists. This protocol was easily followed, even with only 1 generalist on staff at night for the entire laboratory.

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We do a confirmatory ABO/Rh on non-group O patients with no ABO/Rh history using a specimen obtained from a second venipuncture. Computer crossmatches are done using a current blood sample on patients with a negative antibody screen and no history of clinically significant antibody. Immediate-spin (gel) and IgG crossmatches are done using a current blood sample on patients with a positive antibody screen and/or a history of clinically significant antibody.

I'm curious. Do the TJC inspectors cite AABB standards when they see a deviation/variance or do they cite TJC standards? I ask this because when the State of California (also requires facilities to follow AABB Standards) inspects and finds deficiencies they cite CA regulations, not AABB Standards. Also when HFAP inspects and finds deficiencies in a CA facility, they cite HFAP standards, but do not mention AABB Standards. My point is that when non-AABB regulatory agencies require facilities to follow AABB Standards, it doesn't mean that they perform an "AABB" inspection nor do they follow the AABB Inspection Checklist form. In other words, how does TJC determine, whether or not, if a facility is following AABB standards?

I've been using Gel for all routine testing since 1995 and ProVue since 2004-5. All our specimens (EDTA) are initially centrifuged for 3 minutes in a Stat Spin Express centrifuge. You should use only platelet-poor plasma when testing in Gel. Standard laboratory centrifugation does not give you platelet-poor plasma. Part of our standard routine for resolving ABO Plasma Grouping discrepancies and weakly positive antibody screens is to centrifuge the specimen three (3) more times for a total of 9 minutes of high-speed centrifugation and retest in Gel. This will reduce but not entirely eliminate the "sprinkles". To me, "sprinkles" in Gel correspond to the "sticky cells" seen in microscopic reading of standard tube tests. I don't think "sprinkles" are clinically significant. We standardized reading of gel cards using lighted 35mm photographic slide viewer. This viewer has the milky plastic background see in X-Ray viewers and that is used by ProVue.

I don't condemn Standard Tube Testing as much as I abhor the intrinsic variability (increased risk) introduced by workers who were never shown or who never mastered the technique (as practiced by the expert serologists you referenced) to be able to produce consistent results particularly with weak (<=2+ agglutination). Discussions with experts does nothing to address this issue, whereas automated testing completely eliminates the issue of manual (technique-dependent) testing methods.

These quotes are from page 91 of the 1997 ARC Immunohematology publication, "The inconstant degree of agitation that different workers use in resuspending RBC buttons after centrifugation. This can significantly affect the sensitivity of tube tests and explains many instances of variability seen in the performance of proficiency tests", and "Incorrect technique is the most likely cause of unwanted negative tests. Standardized column technologies, such as the gel test, eliminate many of the variables inherent in test tube methods". John Judd also published a white paper through ORTHO regarding use 2-cell versus 3-cell antibody screen reagents probably prior to the ARC Immunohematology publication in 1997. In that white paper, he concluded that difference in test results between 2-cell and 3-cell reagents was attributable to variation in technique between personnel performing the tube tests and not due to antibody screen cells reagent. I believe manual tube testing is the 800lb dinosaur in the room of a 21st century Transfusion Service. The rest of the Clinical Laboratory discontinued manual testing in the 20th century. Automated testing is not just an answer for high volume testing but is critical safety enhancement in even the smallest Transfusion Service.

I would be hard-pressed to justify the use of a 3-Cell screen with automated testing, not so for manual tube testing.

This approach becomes very problematic when dual-population (mixed-field agglutination) is observed in ABO/Rh typing in a highly computerized transfusion service. Do you segregate these patients to a manual system on paper or other type of non-standard handling or do you mainstream the patient in the computer system? I prefer to mainstream these situations so that staff are not forced to rarely used manual systems. One of the main tenets that I taught staff was 'to record what you see, not what you think it should be'. So I designed the computer system to make this possible, without exception. For example, if you see dual-population in gel test, that is what you enter into the computer (there are results mnemonics 4+m versus 4+ to differentiate dual-population from uncomplicated agglutination). The computer is configured to reflex additional tests to the sample which prompt user with additional information and questions. If there is a blood type on file (done prior to transfusion) and there are recent ABO/Rh non-identical transfusions, computer will calculate blood type as Rh Positive when Rh Negative red cells are transfused to an Rh Positive recipient that resulted in the observation of dual-population in the anti-D tube of gel card of a post-transfusion blood sample. That's one heck of a run-on sentence. The same thing will occur if a non-group O recipient is transfused with group O red cells. Your computer system may/may not be able to do this.

John, I used the same system, Biologics, Inc, out of Utah. The beauty of this system was that all samples collected by the phlebotomists were labeled with this system. Secondly, the specimen container labels could only be made at the bedside and that the information on the label was generated from a plastic tag (attached to the patient) that was embossed with patient information. This was a mechanical system that has now been mimicked by electronic systems that generate specimen container label from a barcode on the patient wristband. With this type of system, mechanical or electronic, there is no need for a secondary blood bank identification band.

To confirm you are getting an equivalent of a "hard spin", you should verify that your blood samples have platelet-poor plasma after the two centrifugations. We use the StatSpin Express 3 centrifuges that spin at 7200rpm and produce 4400rcf for 3 minutes. These are the same centrifuges that Coagulation Section uses to prepare platelet-poor plasma for coagulation testing. As part of our protocol for investigating ABO discrepancies in gel and even weakly positive antibody screens, we routinely centrifuge a blood sample 3x for a total of 9 minutes and then retest. This is surprisingly effective.

We use TYPENEX and have no plans to discontinue. The TYPENEX code is an integral part of the process of obtaining the initial blood sample, the second blood sample (if indicated) and blood issue. The code is entered in the computer initially upon receipt/collection, pretransfusion testing and at the time of blood issue. Cross checking of the number is done by computer and all codes must match before testing can be filed/verified and before blood issue routine can be completed in computer.

Were these patients who 'changed' to Rh Negative massively transfused? My experience with ProVue is that Rh Positive patients receiving as few as a single Rh Negative transfusion were graded by ProVue and visually confirmed by user as "dual population" in the anti-D tube of the gel card.

To address this question of safety, I would like to see hard data from the AABB community as to the frequency of events where an ABO discrepancy was detected in the second ABO determination that was not detected in the first ABO determination. More importantly, did the detection of an ABO discrepancy (missed by the first ABO determination) prevent the transfusion of ABO incompatible red blood cells? My responses above assume that the ABO discrepancy was demonstrable by repeat testing of the first blood sample.