The results of the rabbit pyrogen test carried out in different but similarly equipped Institutes on 36 batches of plasma substitute are comparable. If extreme variations occur in the results of the test the cause is not likely to be found in the conditions and execution of the work, as is shown by testing material from the same bottle. When the material is taken from the same bottle the results obtained by the different Institutes are similar. One explanation of the non-comparable results seems to lie in the cleaning of the bottles. It is therefore essential that manufacturers utilize properly washed bottles. Another cause of non-comparable results seems to be linked with the time factor; as it is known from the literature, pyrogen can disappear during storage.
