With a CLL diagnosis, many of us change from our earlier experience of being blithely ignorant of our blood test results, to taking an arguably unhealthy interest regarding each blood test, often worrying unnecessarily due to variations which are of no consequence. I know I certainly took a few years to get comfortable with seeing lots of out of range results and a growing ALC until I became familiar with the new norm for someone with CLL. In answering questions others have posed, I've often pointed out that there is an inherent reproducibility limitation in measuring blood counts. This means that it is quite possible to get several apparently quite different results, perhaps even showing an apparent trend, while each of the apparent different results is within the accepted natural variation possible when machine counting the same sample.
From The Hematology Times (free registration):
"A comparison of commercially available blood tests has revealed more variability than expected, according to researchers.
The group compared basic blood tests run by commercial laboratories and found the testing service, type of test, and time of collection all influenced the accuracy of results.
The researchers collected peripheral blood samples from 60 healthy adults at 4 separate time points within a 6.5-hour window. The samples were collected in Phoenix, Arizona, at an ambulatory clinic and at retail outlets with point-of-care services.
More than half of the test results showed significant differences between test providers. Of the 22 tests, 15 (68%) showed significant variability between labs.
Triglyceride levels and red blood cell counts were among the most consistent results, while white blood cell counts and overall cholesterol levels were among the most variable. (My emphasis - Neil)
In addition, the researchers noted that, although they controlled subjects’ eating and physical activity, data from blood samples collected earlier in the day were sometimes significantly different from samples taken from the same subjects later in the day."
This is why you should minimise other sources of variation in your blood test results by always using the same pathology service, having your blood sample taken around the same time of the day and also following the same daily living pattern prior to your blood test.
Photo: Speaking of punctures, an Echidna (Australia's spiny ant-eater) hunting for food that I was delighted to photograph a few weeks ago. Echidnas lay eggs and suckle their young. If you get too close to one, it will quickly dig into the ground with those powerful legs and leave just those formidable spines exposed. Run over one and you have to throw your tyre away - those spines keep working their way through the tyre. Doesn't do the echidna much good either...