Oh .. and another thing. I do point of care needlestick blood testing on people every day. I check haemoglobin and blood sugar levels. When doing a needlesti

Oh .. and another thing. I do point of care needlestick blood testing on people every day. I check haemoglobin and blood sugar levels. When doing a needlestick test for Hb I always do it twice because these results are often spurious (especially when you "milk" blood out of the finger). The Hb/liter figure can vary by as much as 20-30% routinely. If this is the case I then do a proper venous draw to find the true result. These tests are marginally useful in screening for really low or really high values, but they are pretty much inadequate compared to a proper venous draw for clinical decision making.