<span>After many experiments and many different approaches to the question, the scientist may be able to develop a theory. The theory explains why nature behaves in the way described by the natural law. It answers not only the original question, but also any other questions that were raised during the process. The theory also predicts the results of further experiments, which is how it is checked. Theories are not the end of the process.</span>
CATGGATCCA for future reference this is considered biology, you may get a quicker response if you categorize it as such :)
It is essential for accurate results that the correct volume of blood is sampled to achieve a correct concentration (and dilution, if liquid heparin is used), and that blood and anticoagulant are well mixed immediately after sampling.