Читать книгу Practical Guide to Diagnostic Parasitology - Lynne Shore Garcia - Страница 77

A series of three specimens should be collected on separate days. If possible, the specimens should be collected every other day; otherwise, the series of three specimens should be collected within no more than 10 days. If a series of six specimens is requested, these specimens should also be collected on separate days or within no more than 14 days. Many organisms, particularly the intestinal protozoa, are shed sporadically and do not appear in the stool in consistent numbers on a daily basis; thus, the series of two (minimum) or three specimens is recommended for an adequate examination. Multiple specimens should not be collected from the same patient on the same day. One possible exception would be a patient who has severe, watery diarrhea such that any organisms present might be missed because of a tremendous dilution factor related to fluid loss. These specimens should be accepted only after consultation with the physician. It is also not recommended for the three specimens to be submitted one each day for three consecutive days; however, use of this collection time frame would not be sufficient to reject the specimens.

Although three stool specimens are recommended, laboratories have been more willing to accept two specimens, primarily because of cost savings and the assumption that if the patient is symptomatic, the presence of any organisms is likely to be confirmed by testing two specimens. However, it is important that clients understand the pros and cons of the two approaches. Both collection approaches are being used by diagnostic laboratories.