A talk at Gresham College today on blood microscopy and pathology

When I discovered that Dr Archie Prentice of the Royal College of Pathologists was one of several people doing a free lunchtime talk on 'The Story of Your Blood' at Gresham College today I smiled. He was the expert commentator on an episode of You and Yours talking about a bogus diagnostic blood test that was under investigation by the ASA and which has irritated me for three and a half years.

It irritated me so much that after numerous ASA adjudications (lost count) against a variety of people who sell it, I wrote to the ASA and asked if they would add some CAP guidelines on the test, which they did. I strongly suspect others requested this too as there seem to be rather a lot of people who've reported this misleading blood test to the Advertising Standards Authority.

Today was about celebrating three objects used in the everyday lives of pathologists, and part of the wider 'A history of pathology in 50 objects' that was published by the RCPath in 2010 to celebrate their 50th anniversary. I picked up a copy of the booklet (they were handing them out free) and got stuck in on the train home. It's FANTASTIC. There's an online version but the physical copy is a lovely thing, with each page having a little introduction to a particular object / tool that's used now or in the past by pathologists. Obviously I was pleased to see a mention of the AMES Reflectance Meter (the first blood glucose meter) and Dextrostix (aka Boehringer Mannheim [BM] sticks) for testing blood glucose levels in diabetes.

Dr Prentice spoke first and gave an overview of the history of pathological investigations into blood and then Dr Deepti Radia spoke about three objects that she uses on a daily basis (microscope, glass slide and Coulter counter, which automatically does a cell-count saving a lot of time). Finally Dr Joel Newman gave some patient journey examples of what might lead someone to a blood testing unit (medical assessment unit) and what might be gleaned from their blood smear and other blood tests.

Joel's talk made me even more angry at those who flog bogus diagnostic blood tests than I was before. He mentioned that a blood smear could indicate some blood cancers (the presence of a lot of white blood cells is indicative) though other tests would confirm more strongly. He gave examples of two patients with CML (chronic myeloid leukaemia) and CLL (chronic lymphocytic leukaemia). In one, I'm afraid I've forgotten which, it was previously a fairly poor prognosis but with a new drug (imatinib, quite pricey) people can remain in good health for a long time - as Archie noted later, perhaps until they die of something else like old age! In another the condition is one that just needs close monitoring and both cases require regular blood tests to see that all is well, or not.

The idea that someone might be told by someone with minimal science qualifications that they have "markers for cancer" (when it turns out that they do not) and might need vitamins or other supplements (just listen to that radio programme linked above) made me quite livid. A real blood test by someone competent, taken under appropriate conditions with the appropriate awareness of symptoms and perhaps medical history could actually tell someone what type of cancer they have, if they have it, and whether or not a particular treatment is the most appropriate response, or if it should just have an eye kept on it.

Archie also mentioned that he gets to write difficult exam questions and gave an example where someone might be asked to discuss the pros and cons of treating someone, who has a very particular form of blood cancer, with one of the drugs like imatinib long-term versus giving them a stem cell transplant that would replace their iffy cells with new unaffected ones. (Note that stem cell transplants aren't suitable for everyone).

And apparently such transfusions can change your blood type - and I think I heard someone say that in exceptionally rare circumstances blood type can even change spontaneously (!). Wikipedia mentions something about infection or autoimmunity etc. News to me anyway. Though I am familiar with the chimaera stories of people being told that their relations aren't theirs, because the blood tests imply no match, though tissue samples indicate that they really are (briefly: they are the combination of two, fused non-identical twins in one body).

Previous experience suggests that notes from the talk will shortly appear on Gresham's site so if you're interested it's worth visiting the first link again later.