Reference ranges for blood tests are sets of values used by a health professional to interpret immunology david male pdf set of medical test results from blood samples. Blood test results should always be interpreted using the reference range provided by the laboratory that performed the test.
It is determined by collecting data from vast numbers of laboratory tests. The precise factor depends on hematocrit as well as amount inside RBCs.
United Kingdom and other parts of Europe and Australia and New Zealand. AST, ALT, LD and γ-GT in Sweden.
If not otherwise specified, a reference range for a blood test is generally the venous range, as the standard process of obtaining a sample is by venipuncture. An exception is for acid-base and blood gases, which are generally given for arterial blood.
Arterial levels for drugs are generally higher than venous levels because of extraction while passing through tissues. This may also be called standard range.
For most substances presented, the optimal levels are the ones normally found in the population as well. More specifically, optimal levels are generally close to a central tendency of the values found in the population.
In addition, some values, including troponin I and brain natriuretic peptide, are given as the estimated appropriate cutoffs to distinguish healthy people from specific conditions, which here are myocardial infarction and congestive heart failure, respectively, for the aforementioned substances. References range may vary with age, sex, race, pregnancy, diet, use of prescribed or herbal drugs and stress. Reference ranges often depend on the analytical method used, for reasons such as inaccuracy, lack of standardisation, lack of certified reference material and differing antibody reactivity. Also, reference ranges may be inaccurate when the reference groups used to establish the ranges are small.