Survey of clinical laboratory practices for parasitic diseases.

To gain knowledge about laboratory testing practices for parasitic diseases, in 2000 we surveyed 562 laboratories in 9 US states, and 455 (81%) responded. Most laboratories (59%) indicated that they send specimens off site for parasite screening, and most laboratories (89%) did not routinely test fecal specimens for Cryptosporidium species, Cyclospora cayetanensis, or microsporidia, unless testing for these organisms was specifically requested by a physician. Only 39 laboratories offered serological testing for Toxoplasma gondii, and most (78%) that had their results confirmed did so at national commercial laboratories rather than a Toxoplasma reference laboratory. Because most clinical laboratories do not routinely test fecal specimens for Cryptosporidium species, C. cayetanensis, or microsporidia, physicians must request specific testing for these organisms when they are clinically suspected; because of this lack of routine testing, it is difficult to estimate the true burden of disease due to these organisms.