Hozman

I will quote (one of my favourite quotes) from Issitt Peter D and Anstee David J.  Applied Blood Group Serology.  4th edition, 1998, Montgomery Scientific Publications, pages 63-64 (only because I cannot get to my copies of earlier editions at the moment - as while looking for them, a large number of my text books almost knocked me sideways, as they fell off the top of my wardrobe, and my wife nearly "brained" me too for making our bedroom look a mess!).
"Reading Methods for In Vitro Tests.
Now that most routine tests are carried through to an antiglobulin reading the question of how to read them does not often arise.  They are usually read macroscopically in order that the cells and serum are left in the tube for progression of the test.  A few cells may, of course, be removed and examined microscopically at any stage if this type of reading is required.  However, one of us (PDI) has believed for years that routine use of the microscope in the blood bank creates far more problems than it solves.  Almost any cell suspension, including those in which washed cells have never been exposed to antibody, if examined carefully enough under the microscope will be found to contain a few small clumps of red cells.  Thus, while reading aids such as mirrors or hand lenses are acceptable, routine use of the microscope is not condoned.  This reasoning also applies to the reading of antiglobulin tests.  Again if agglutination cannot be seen with the naked eye, a hand lens, a convex mirror, or the type of microscope in which the contents of the tube are viewed while still inside the tube by placing the tube itself on the microscope slide, IT IS NOT THERE.  Were it not for special tests, such as those in which mixed-field reactions may have occurred or when a small percentage of fetal cells might be present in a maternal sample, the microscope should be banned from the blood bank.
Enzyme tests for agglutination or following conversion to antiglobulin reading, should NEVER be read microscopically."
Several things should be noted about this quote.
Firstly, there is NO distinction here between the indirect and direct antiglobulin test.  Peter Issitt (see PDI, although I happen to know that Dave Anstee agrees with him) talks about reading antiglobulin tests.
Secondly, this quote was originally written well before 1998.  Since that time, there have been huge steps made in improving the sensitivity of tests within blood transfusion and blood group serology (often at the expense of specificity, and certainly at the expense of making diagnosis from the results of these tests straightforward - see the introduction of the term "delayed serological transfusion reaction", when there is laboratory evidence of a transfusion reaction, but no clinical evidence of a "delayed haemolytic transfusion reaction" (Petz LD and Garratty G.  Immune Hemolytic Anemias, 2nd edition, Churchill-Livingstone, 2004).
Thirdly, both Peter Issitt (1986) and Dave Anstee (1997) have been awarded the AABB Emily Cooley Memorial Award and Lectureship (amongst numerous other international awards - Dave was the President of the British Blood Transfusion Society, the Kenneth Goldsmith Award in 1985 and the James Blundell Award in 2003; these two are far from idiots!
Lastly though, looking down a microscope is no panacea to detecting a transfusion reaction.  I would draw your attention to Sachs UJH, Röder L, Santoso S, Bein G. Does a negative direct antiglobulin test exclude warm autoimmune haemolytic anaemia? A prospective study of 504 cases.  British Journal of Haematology 2006; 132: 651-661.  This paper talks about the production of de novo antibodies and anamnestic antibody production post-transfusion, as well as WAIHA.  It comprehensively debunks the fallacy that a mixed-field reaction can, in all cases, be detected by the use of a microscope.
So, perhaps the question should be, if the DAT is negative to the naked eye, should we perform an elution in each case?  I REALLY, REALLY hope that nobody (seriously) answers YES to that suggestion (believe me, it was made with my tongue very firmly in my cheek)!
Sorry about the rant!

UVblood: the irradiation devices that this conversation is focused on is not for pathogen reduction or sterilization. In this application, irradiation is used to damage the DNA of T-lymphocytes of donor origin so that they cannot replicate in the recipient and cause a sometimes fatal condition called Graft-versus-Host Disease.

As stated above, currently, the only source of an X-ray radiation source, blood irradiator in North America is Best Theratronics, Canada. This system is currently designated Raycell. This system was initially designed, manufactured and commercially offered to blood processing laboratories in the U.S. in the 1998-1999 time frame. It was designated as the RS 3000. In 2003, this system was licensed to MDS Nordion at which time it was designated the Raycell by Nordion. In latter 2007, MDS Nordion sold its entire irradiation product line (radioactive sources Cs-137 and Co-60), icluding Raycell, to Best Medical.
Other than blood bag canister volume and the addition of an energy reflecting liner? In the canister, Raycell’s design has not changed since the initial design. It lacks a number of features important for current blood irradiation procedure.
There is rumoured pricing over the past several years ranging from $146,000. to $250,000. USD with rumoured annual maintance agreements costs ranging from $10,000. to $22,000. USD.
The major problem with all X-ray radiation source, blood irradiation equipment, available in North America and in Italy and Japan, lies in the use of X-ray sources (tubes) designed for imaging and not as radiation sources. The basic technology has not changed over the past 100 years. Over time the technology used in these tubes results in non-reliability of the X-ray tubes. Unfortunately, blood processing laboratories have born the brunt of the problem as reflected in the high initial cost of the systems and high maintenance costs. The exorbitant initial cost of the equipment is a result of large company overhead and no competition. The high maintenance cost reflects the use of commercially available, industrial imaging X-ray tubes and their replacement.
The exorbitant pricing makes it very difficult for the small to medium size blood processing laboratory to both cost justify the initial cost of the equipment and its on-going maintenance cost.
The Irradiation Machines advertisement below your post lists irradiation equipment designed for research and other applications; not for blood irradiation. As such it has no FDA clearance for blood irradiation.

We only do weak D on babies and donors. However, I have some pts (including 3 where I work) whose D typing in gel is marginally positive, tube testing D on these women is vw+ in all phases tested. They are A+ blood donors. 2 of them were OB pts and I told the docs we were going to give them RhIg and treat them like they were Rh=. Of interest is that I had the Quotient D typing panel. All three women had the same reactions with that panel, yet they aver they are unrelated. Interesting but of no clinical signficance as for as a Transfusion service goes.
I also think that one must interpret vw gel D rxs with caution. There are many and varied comments on how to interpret anti-D rxs <4+ in gel. One has to find a comfort level but be prepared to step out of the box for these margnal rxs.

We don't do weak D on adults, so all Rh neg moms (with pos babies) get Rhogam.