Malcolm Needs

Vis-a vis Sc:-3 blood, I remember when I was working as a VERY junior member of staff in the IBGRL Red Cell Reference Laboratory of Dr Carolyn Giles and Joyce Poole, we did a family study following the relatives of an Sc:-3 female in a small village in Papua New Guinea (PNG), and we found six others.  This was at least 40 years ago now, but it may be worthwhile contacting the PNG Blood Service to see if any of them are still donors, or, indeed, if they have found any other such donors.

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And here we are after just one week.  Getting very close!

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My Score FAIL That's embarrassing!!!!!!!!!!!!!!!!!!!!!  

The following references may be of interest:
Leger RM, Garratty G. Weakening or loss of antibody reactivity after prewarm technique. Transfusion. 2003 Nov;43(11):1611-4. doi: 10.1046/j.1537-2995.2003.00563.x. PMID: 14617322
From the abstract of the above publication:
 
"Results: PW PBS-IAT and PW LISS-IAT showed that 40 and 47 percent of antibodies were weakened, respectively, compared to LISS-IAT; reactivity for 14 percent of antibodies was completely lost by each PW method. By PW PBS-IAT, 34 percent of antibodies were weakened compared to PBS-IAT. PW PEG-IAT showed weakened reactivity by 56 percent of antibodies compared to PEG-IAT; reactivity of seven out of seven PEG-dependent antibodies was completely lost. Of 67 antibodies, 19 percent were defined as low affinity. Of 64 samples tested by the PW method and for low-affinity antibodies, only 6 of 30 that showed decreased reactivity by the PW method appeared to be due to low-affinity antibodies; only 6 of 12 samples that appeared to contain low-affinity antibodies also showed decreased reactivity by the PW method.
Conclusion: Antibody reactivity of potentially clinically significant antibodies can be decreased or missed by PW methods. Antibody enhancement media does not ensure antibody detection by PW methods."
Other publications of possible interest:
Storry JR, Mallory D. Misidentification of anti-Vel due to inappropriate use of prewarming and adsorption techniques. Immunohematology. 1994;10(3):83-6. PMID: 15945800.
Hopkins C, Walters TK. Thermal amplitude test. Immunohematology. 2013;29(2):49-50. PMID: 24094235.
Dupuis S. Use of the prewarm method for detecting clinically significant alloantibodies in the presence of cold autoantibodies. Immunohematology. 2018 Dec;34(4):148-150. PMID: 30624948.

We have been using pre-warming in the UK since before I started in Blood Transfusion (circa 1973) and we have never had a clinically significant transfusion reaction caused by warming away an antibody in all that time.
Yes, there have been occasions when, for example, an anti-S has disappeared by pre-warming, but, if you look in most text books, and all reliable text books, anti-S is only rarely clinically significant - and certainly none of those that we have "warmed away" have caused any transfusion reactions at all.
There was one case of an anti-Vel causing a fatal transfusion reaction, BUT, that was not missed through pre-warming; that was missed because EDTA plasma was used, and the anti-Vel could only be detected in serum (confirmed by the IBGRL), and so I think that the worries about pre-warming are vastly over estimated.
It is vital to keep up with competency for this technique, as with any other technique, but probably more so with this technique.

Yes!

I don't think the AABB comments are evidence based.  Washing with 37 degree saline is extremely unlikely to cause false negatives with clinically significant antibodies,  and I'm unaware of any evidence that this is so.  Any such antibody would be very low affinity to be washed away by saline at any temperature, and unlikely to have in vivo/clinical significance. 
As argued persuasively above by Malcolm Needs, anything that doesn't react at 30 degrees or above in typical serologic testing isn't going to cause clinical problems.  Patients are neither at 30 degrees nor centrifuged :).  Our serologic techniques are overly sensitive,  in general,  for clinically insignificant agglutinins. 
No need for cold panels ever, with rare exception, and more for intellectual curiosity than clinical decision making.  Perhaps a mini-cold screen someetimes just to confirm you are indeed detecting a weak cold agglutinin in 37 degree testing, which disappears with prewarm technique. 
Like Malcolm, I've never seen a patient with an hemolytic reaction due to an antibody that disappears with prewarming, in close to 50 years of clinical practice.  I know there are in vitro examples of clinically significant antibodies that weaken or disappear with prewarm, but I've never seen any clinical consequences.

or 12. 
As I mentioned, it is imperfect data, but overall, I think it likely reflects our staffing ages.

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I'm sorry, but I just don't believe the member who says they are 122 (Oh, I dunno though - I've just looked in the mirror!!!!!!!!!!!!!!!!!!!!).

This is a chart of our members by age.
It only includes those who gave a year of birth and are not banned members.  That came to 6,920 people.  There is no data validation on this; some people may have filled in just anything or mistakenly entered incorrect data.  With this large volume of data, the few stray values are likely nullified by the people who want to provide correct data.
 

Cliff, I've been glancing at the birthday list and it got me thinking (dangerous, I know), how hard would it be to run an algorithm that could calculate either the average age or the median age of group members.  It might give us some perspective on the need to recruit more people into the profession.  Just a random thought.

 

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I'm not sure if this is still the case but the IS step was intended to confirm ABO compatibility.   

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Most certainly, you need to have a thorough transfusion history on the patient, as my good friend Yanxia says above, but it also depends upon the condition of the patient.  If the patient is exsanguinating, the old adage comes into play that it is not a medical triumph to give perfectly compatible blood to a corpse, when, in very many cases these days, a haemolytic transfusion reaction can be treated.  HOWEVER, it is ALWAYS a decision to be made by a medically qualified person, rather than a laboratory qualified person to make, as to how urgent the transfusion may be.

IF there is time, it is always worthwhile doing a few more investigations.  For example, is the patient DAT Positive, and, if so, is it IgG, IgM, IgA (rare), complement or a combination?  Is the reaction seen in the auto-control due to a "cold" auto-antibody, or something else.

To repeat what I wrote above, it MUST always be a decision for a medically qualified person, rather than a "lab rat" (HATE that term, but I hope you know what I mean, without taking offence - being a retired "lab rat" myself), but, if it was a case with which I was dealing, apart from doing a few basic tests (see above) I would be happy to give the blood - and more importantly, receive the blood, if I were the patient.