I’m 62 years old and I have had DM2 for 10 years now. I currently use sulfonylureas and metformin. Because I have never really had good HbA1c, my GP prefers to check it 4 times a year. So I have done this blood test it I think around 40 times until today. The last three months I’ve done my best with diet, exercise and when I got the result today HbA1c 8,2% I found it very suspicious and I´m not convinced it is the right result. You may be thinking that´s just an excuse, but now comes the most interesting part: last time I went to the lab there was this very strange woman who took my blood and almost didn’t look at me at all. And: the collecting tube has a GREEN top. As far as I can remember every time I measure my HbA1c the top of the tube was lavender purple color. I suspect this result is because of the wrong tube! Does anybody know something about this?
Hello! I think that’s not the reason for your result. I will explain: You are right that collecting the proper specimen and identifying the different types of blood collection tubes is very important. Not every color can be used for every exam. For HbA1c the lavender top tube, which contains EDTA (and you are right that it has been used before) the recommended one. But the green top if it has lithium heparin; it is an alternative because it won’t affect the result. The only effect of the lithium heparin is to inactivate “coagulation substances” thrombin and thromboplastin. But what I would do if I were you is to calling the lab and ask them whether this green tube can be used for HbA1c. If they are using this regularly and it was no mistake they will certainly know. Also discuss with your doctor other possibilities for higher HbA1c: you may be arriving a point where the dose of the drugs are not enough anymore to keep your BG in good values despite the right diet and sport, or you may have taken medications that interfere with the measurement. And in some cases anemia can also be a reason.
The best thing to do is to call the lab. You can tell them exactly what you saw that day and explain to them that you have always seen a lavender tube used for your HbA1c. It is best to call them so you have piece of mind knowing they are doing the correct test. I hope that you get your answer in a respectful way.