Animal health and blood numbers

It is often (incorrectly) claimed that a healthy dog has a wet nose (or vice versa). If that were true and I was a dog I would be regarded as being healthy! Since March I have had a slightly damp nose. Not sure why – it’s not listed among the many side effects of Docetaxel or of Triptorelin, so it’s a bit of a mystery.

Meanwhile I have continued trying to get blood out of a stone (aka my finger) and had my latest platelet count and consultation. Not quite as high as the last number but probably within the margin of error for platelet counts, so OK. After a quick consultation with the bosses the registrar said I should continue with prednisolone at 5mg a day for three weeks and then stop. I should then go back and see haematology a week later so that we could see what had happened. Suck it and see medicine! but an approach I am quite happy with in this instance.

This set me to thinking, so I googled “how are platelets measured?” and found plenty of sites that told me what the right platelet levels are and so on but none that answered my question. I eventually stumbled on one that looked as though it might be what I wanted.  It told me “Platelet clumps are more numerous in samples collected from small peripheral veins, rather than larger veins like the cephalic or jugular” (I don’t fancy the phlebotomist going for my jugular). “The presence of platelet clumps (at the feathered edge or throughout the smear) will decrease a platelet count obtained by any method (estimation, electronic or manual) and may even invalidate the count.” All good stuff but it didn’t give me a figure. It then went on to say “Cats have notoriously reactive platelets, which clump readily on sample collection. Therefore, obtaining a platelet count can be difficult in a cat.” OK so I was looking at a veterinary website! Still I suppose that blood analysis must be pretty much the same for humans and for other mammals. (Interestingly it appears that birds and fish don’t have platelets).

I kept digging and found that platelets appear as spots, about 20% the diameter of red blood cells but that platelets that are too large or too small do not get counted. Some analysers may not be able to correctly distinguish tiny clumps of platelets and nucleated red blood cells. Platelets clump when they are doing their job and stopping bleeding, however clumps may be misclassified as leukocytes or erythrocytes (red or white blood cells to the less medically erudite of us).

So I haven’t found an absolute figure for the margin of error on platelet counts but I did find a report of one person getting two separate counts done on the same blood sample and getting readings of 3 platelets per nanolitre first time and 6 platelets per nanolitre the second time!  Therefor it looks like a variation from one test to another of perhaps 10 platelets per nanolitre is more likely to be down to the margin of error and/or the day to day variation in the number of platelets pootling around in my blood than to any significant underlying change.

Back in the blood-out-of-a-stone department I am not convinced that the lancing machine is working as well as it could but I have managed to get a few readings. It is bumbling along at around 8-9 mmol/l at the moment and hopefully won’t change too much over Christmas provided I behave myself. I have also started a graph to track it which set me to thinking can I get all my key readings on to one graph? (You may have noticed I quite like graphs).

Creating a single key numbers graph is not easy because of the wide variation in the range of values and in timescales.  I have PSA peaking at 17 and dropping to 0.2, Platelets should be 200 plus but mine are currently running at 10 to 50, weight 71 to 76 kg, blood glucose up to 10, HbA1C 40 to 70, neutrophils 0 to 7, and white blood count 2.9 to 10. I could set a notional target or average and show each as a percentage of that, but there is another problem.  I (and others) have been monitoring some of these key readings since last December while others have only been logged over the last few weeks or months. So probably the best I could do is two graphs – one covering the period from the beginning of the year and the other the last few months.

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There is somewhere between a 10% and a 90% chance that this is my last post of this year so perhaps I should wish my reader a Merry Christmas or a belated Happy Hanukkah or whatever and all the best for 2017.

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4 thoughts on “Animal health and blood numbers

  1. Tim, As I’m sure you know you can use logarithmic axes (one or both) for graphs where you are dealing with a wide range of values. Have a good Xmas

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