water, aliquot 0.4 ml into tubes, and evaporate the water. This amount of anticoagulant is sufficient for 10 ml of blood. One can also use 20 mg of EDTA (dry) per tube (20 mg/10 ml of blood).
The time when the specimen was drawn should be clearly indicated on the tube of blood and also on the result report. The physician will then be able to correlate the results with any fever pattern or other symptoms that the patient may have. There should also be some comments on the test result report that is sent back to the physician that one negative specimen does not rule out the possibility of a parasitic infection.
STAT Test Requests and Risk Management Issues
All requests for malaria diagnosis are considered STAT requests, and specimens should be collected, processed, examined, and reported accordingly. All requests for examination of blood films should include a possible diagnosis of malaria; thus, these requests are always considered STAT. Not only the blood collection should be considered STAT, but also the processing and examination of both thick and thin blood films should be performed immediately on receipt of the blood (Table 3.6). Immunologically naive individuals with no prior exposure to malaria often present to the emergency room or clinic with symptoms such as fever and malaise and a relevant travel history to an area of the world where malaria is endemic. These patients often have vague symptoms, but have the potential to become very ill with malaria, even with a low parasitemia (0.0005% to 0.1%).
Collection of Specimens from Other Body Sites
Although clinical specimens for examination can be obtained from many other body sites, these specimens and appropriate diagnostic methods are not as commonly performed as those used for the routine stool specimen. The majority of specimens from other body sites (Table 3.7) would be submitted as fresh specimens for further testing. More information is given in the discussion of specific procedures in Section 5.
*Dientamoeba fragilis trophozoites can be found in formed stool specimens.
Suggested Reading
Beaver, P. C., R. C. Jung, and E. W. Cupp. 1984. Clinical Parasitology, 9th ed. Lea & Febiger, Philadelphia, PA.
Brooke, M. M., and M. Goldman. 1949. Polyvinyl alcohol-fixative as a preservative and adhesive for protozoa in dysenteric stools and other liquid material. J. Lab. Clin. Med. 34:1554–1560.
Code of Federal Regulations. 1991. Occupational exposure to bloodborne pathogens. Fed. Regist. 29CFR1910.1030.
Garcia, L. S. 2007. Diagnostic Medical Parasitology, 5th ed. ASM Press, Washington, DC.
Garcia, L. S. (coordinating ed.). 2008. Laboratory Procedures for Diagnosis of Blood-Borne Parasitic Diseases. Cumitech 46. ASM Press, Washington, DC.
Garcia, L. S. (coordinating ed.). 2003. Selection and Use of Laboratory Procedures for Diagnosis of Parasitic Infections of the Gastrointestinal Tract. Cumitech 30A. ASM Press, Washington, DC.
Garcia, L. S., R. Y. Shimizu, T. C. Brewer, and D. A. Bruckner. 1983. Evaluation of intestinal parasite morphology in polyvinyl alcohol preservative: comparison of copper sulfate and mercuric chloride base for use in Schaudinn’s fixative. J. Clin. Microbiol. 17:1092–1095.
Garcia, L. S., R. Y. Shimizu, and D. A. Bruckner. 1986. Blood parasites: problems in diagnosis using automated differential instrumentation. Diagn. Microbiol. Infect. Dis. 4:173–176.
Garcia, L. S., R. Y. Shimizu, A. Shum, and D. A. Bruckner. 1993. Evaluation of intestinal protozoan morphology in polyvinyl alcohol preservative: comparison of zinc sulfate- and mercuric chloride-based compounds for use in Schaudinn’s fixative. J. Clin. Microbiol. 31:307–310.
Hiatt, R. A., E. K. Markell, and E. Ng. 1995. How many stool examinations are necessary to detect pathogenic intestinal protozoa. Am. J. Trop. Med. Hyg. 53:36–39.
Horen, W. P. 1981. Modification of Schaudinn fixative. J. Clin. Microbiol. 13:204–205.
Melvin, D. M., and M.M. Brooke. 1982. Laboratory Procedures for the Diagnosis of Intestinal Parasites, 3rd ed. U.S. Department of Health, Education, and Welfare publication no. (CDC) 82-8282. Government Printing Office, Washington, DC.
NCCLS/CLSI. 2000. Laboratory Diagnosis of Blood-Borne Parasitic Diseases. Approved guideline M15-A. NCCLS/CLSI, Wayne, PA.
NCCLS/CLSI. 2005. Procedures for the Recovery and Identification of Parasites from the Intestinal Tract. Approved guideline M28-2A. NCCLS/CLSI, Wayne, PA.
Scholten, T. H., and J. Yang. 1974. Evaluation of unpreserved and preserved stools for the detection and identification of intestinal parasites. Am. J. Clin. Pathol. 62:563–567.
Yang, J., and T. Scholten. 1977. A fixative for intestinal parasites permitting the use of concentration and permanent staining procedures. Am. J. Clin. Pathol. 67:300–304.
Table 3.1 Fecal specimens for parasites: options for collection and processinga
Suggested Reading
Cartwright, C. P. 1999. Utility of multiple stool specimen ova and parasite examinations in a high-prevalence setting, J. Clin. Microbiol. 37:2408–2411.
Hiatt, R. A., E. K. Markell, and E. Ng. 1995. How many stool examinations are necessary to detect pathogenic intestinal protozoa? Am. J. Trop. Med. Hyg. 53:36–39.
Kehl, K. S. C. 1996. Screening stools for Giardia and Cryptosporidium: are antigen tests enough? Clin. Microbiol. Newsl. 18:133–135.
Morris, A. J., M. L. Wilson, and L. B. Reller. 1992. Application of rejection criteria for stool ovum and