The ratio of errors belonging to preanalytical phase, which is a part of total testing process is extremely high. The errors should be reduced by including the preanalytical phase in quality assurance as much as possible. ISO 15189 recommend external quality assurance for preanalytical phase. Although in limited numbers, external quality assurance programs may be classified under three headings: Type I: Registering the erroneous procedures, Type II: Determining the erroneous samples, Type III: Registration of occured errors. These programs, having various advantages and disadvantages, may be seen as complementary to each other. Although it is new for our country, it was aimed to evaluate the preanalytical external quality assurance which is performed for years all around the world.