August 10th, 2008


Everything You Always Wanted To Know About Platelets

Not really, but I've learned (or re-learned) a lot about platelets in the last 24 hours. I guess having the discussion with the vet tech friend of ours got me thinking of this situation from a different angle. Instead of doing research on thrombocytopenia and it's causes and treatment, I've been researching how platelets are counted and how reliable the results are when they're estimated (as several of Devon's results have been).
It actually only took me about 15 minutes to find about a dozen different sources online that all say the same thing: any blood sample that has clumped platelets can't be counted accurately by any analyzer or human. Just the fact that there are clumps present precludes the possibility of even getting a decent estimate of the total number of platelets circulating in the blood.

I did find one site that explained how an estimate can be determined but it only uses the platelets that aren't clumped and doesn't take into account the ones that are in the clumps. So you have an estimate but how good is it? I guess if the estimate you get is in the normal range, all is well. If not, how can it be helpful since you don't have any idea how many platelets are in the clumps?

I also found a couple of suggestions for getting a non-clumped sample. One suggestion was to draw a red top tube before drawing the purple top (or EDTA) tube. Another was to use sodium citrate instead of EDTA but it also said that due to the dilution factor of the sodium citrate, a mathematical equation had to be applied to get an accurate count.

But in the absence of any other abnormality in the CBC and the lack of any other clinical signs or symptoms in the patient, why not just assume that the platelets are fine, they're there and doing their job and the patient is fine?

So, I sent an email to my vet asking her to find out if there's some way we can get an accurate platelet count before we go any further. And I will be tapering Devon off of the Prednisone as soon as I can.

I simply can't understand why--if I can find this information so easily and quickly--my vet hasn't seemed to consider that we might be acting on false information. When I told a friend about this, a friend who also uses this vet, she said it sounded to her as if my vet is burned out and has lost her curiosity. Normally I'm not really interested in assigning blame in these kinds of cases, that is as long as I feel that the person has really tried but simply made an error in judgment. But if it's a case where the person didn't make an effort--especially when it comes to the well-being of my dog, I just see red. I haven't slept well in weeks, especially since Friday night. Last night I had to take a Benedryl to sleep because I was so worked up about it and I just know I'm not going to handle it well when I next speak to her.

I should probably just be happy that Devon's OK but I keep noticing that my jaw is clenched. I keep coming back to how very simple it would be for her to have just picked up the phone and called someone at the vet school and asked them what they would do if they had a blood sample with clumped platelets. And I also can't avoid thinking that at least part of the reason I'm so angry is that I feel guilty for letting my dog be treated with Prednisone for 4 weeks when it seems to have been completely unnecessary.