Especially in laboratory medicine reference values are used to classify measured values at all can and thus can provide guidance whether this parameter is pathological ( diseased ) or not.
Reference values are determined statistically from findings in healthy subjects. Such results are referred to as normal, which are found in about 95 percent of all healthy examinees. In this case, the confidence interval is selected such that in each case at the upper and at the lower end of the measured values are a 2.5% of the values of all the test persons.
Thus, there is not a single normal value, but a certain fluctuation range within which all values regarded as normal. This area is called the reference or normal range. In addition, dependence on age, gender, region, race, or made through the use of different measurement methods.
For the interpretation of laboratory parameters, it is important to know that the reference ranges for the same parameters - are highly variable - depending on the analysis method and the instrument used. Therefore, should always be stated to each analysis, the respective reference ranges.
There is also a reference or normal range for the sick. This normally is significantly above or below the Healthy. For example, the normal value of blood glucose from 60 to 100 mg / dl. A blood sugar sick with 130 mg / dl consequently has laboratory values , although higher than that of the normal population; for his illness, they are still within the reference range.
Diagnostic reference value
Were on a proposal from the Commission on Radiological Protection in Germany in 2003, established by the Federal Office for Radiation Protection DRLs for radiopharmaceuticals and published in the Federal Gazette. This includes reference values of Radiopharamaka for frequent, as also included for dose- intensive nuclear medical examination procedures. Exceeding these reference values require justification by an expert nuclear medicine physicians and must be documented accordingly.
Units of the SI system of units:
Unit - Declaration
G / dl - 1 gram per deciliter (100 milliliters)
Mg / dl - 1 milligram ( one thousandth of a gram ) per deciliter
Ug / dl - 1 microgram ( one millionth of a gram ) per deciliter
Ng / ml - 1 nanogram (1 billionth of a gram ) per milliliter
Meq / l - milligrams equivalent - one thousandth of the amount of substance that is equal to a reference atom ( hydrogen).