Abstract
Objective - To assess the use of CSF testing with an indirect fluorescent antibody test (IFAT) for diagnosis of equine protozoal myeloencephalitis (EPM) caused by Sarcocystis neurona. Sample population - Test results of 428 serum and 355 CSF samples from 182 naturally exposed, experimentally infected, or vaccinated horses. Procedure - EPM was diagnosed on the basis of histologic examination of the CNS. Probability distributions were fitted to serum IFAT results in the EPM+ and EPM- horses, and correlation between serum and CSF results was modeled. Pairs of serum-CSF titers were generated by simulation, and titer-specific likelihood ratios and post-test probabilities of EPM at various pre-test probability values were estimated. Post-test probabilities were compared for use of a serum-CSF test cobination, a serum test only, and a CSF test only. Results - Post-test probabilities of EPM increased as IFAT serum and CSF titers increased. Post-test probability differences for use of a serum-CSF combination and a serum test only were ≤ 19% in 95% of simulations. The largest increases occurred when serum titers were from 40 to 160 and pre-test probabilities were from 5% to 60%. In all simulations, the difference between pre- and post-test probabilities was greater for a CSF test only, compared with a serum test only. Conclusions and clinical relevance - CSF testing after a serum test has limited usefulness in the diagnosis of EPM. A CSF test alone might be used when CSF is required for other procedures. Ruling out other causes of neurologic disease reduces the necessity of additional EPM testing.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 869-876 |
| Number of pages | 8 |
| Journal | American Journal of Veterinary Research |
| Volume | 67 |
| Issue number | 5 |
| DOIs | |
| State | Published - May 2006 |
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Cite this
Indirect fluorescent antibody testing of cerebrospinal fluid for diagnosis of equine protozoal myeloencephalitis. / Duarte, Paulo C.; Ebel, Eric D.; Traub-Dargatz, Josie; Wilson, William D; Conrad, Patricia A; Gardner, Ian.
In: American Journal of Veterinary Research, Vol. 67, No. 5, 05.2006, p. 869-876.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Indirect fluorescent antibody testing of cerebrospinal fluid for diagnosis of equine protozoal myeloencephalitis
AU - Duarte, Paulo C.
AU - Ebel, Eric D.
AU - Traub-Dargatz, Josie
AU - Wilson, William D
AU - Conrad, Patricia A
AU - Gardner, Ian
PY - 2006/5
Y1 - 2006/5
N2 - Objective - To assess the use of CSF testing with an indirect fluorescent antibody test (IFAT) for diagnosis of equine protozoal myeloencephalitis (EPM) caused by Sarcocystis neurona. Sample population - Test results of 428 serum and 355 CSF samples from 182 naturally exposed, experimentally infected, or vaccinated horses. Procedure - EPM was diagnosed on the basis of histologic examination of the CNS. Probability distributions were fitted to serum IFAT results in the EPM+ and EPM- horses, and correlation between serum and CSF results was modeled. Pairs of serum-CSF titers were generated by simulation, and titer-specific likelihood ratios and post-test probabilities of EPM at various pre-test probability values were estimated. Post-test probabilities were compared for use of a serum-CSF test cobination, a serum test only, and a CSF test only. Results - Post-test probabilities of EPM increased as IFAT serum and CSF titers increased. Post-test probability differences for use of a serum-CSF combination and a serum test only were ≤ 19% in 95% of simulations. The largest increases occurred when serum titers were from 40 to 160 and pre-test probabilities were from 5% to 60%. In all simulations, the difference between pre- and post-test probabilities was greater for a CSF test only, compared with a serum test only. Conclusions and clinical relevance - CSF testing after a serum test has limited usefulness in the diagnosis of EPM. A CSF test alone might be used when CSF is required for other procedures. Ruling out other causes of neurologic disease reduces the necessity of additional EPM testing.
AB - Objective - To assess the use of CSF testing with an indirect fluorescent antibody test (IFAT) for diagnosis of equine protozoal myeloencephalitis (EPM) caused by Sarcocystis neurona. Sample population - Test results of 428 serum and 355 CSF samples from 182 naturally exposed, experimentally infected, or vaccinated horses. Procedure - EPM was diagnosed on the basis of histologic examination of the CNS. Probability distributions were fitted to serum IFAT results in the EPM+ and EPM- horses, and correlation between serum and CSF results was modeled. Pairs of serum-CSF titers were generated by simulation, and titer-specific likelihood ratios and post-test probabilities of EPM at various pre-test probability values were estimated. Post-test probabilities were compared for use of a serum-CSF test cobination, a serum test only, and a CSF test only. Results - Post-test probabilities of EPM increased as IFAT serum and CSF titers increased. Post-test probability differences for use of a serum-CSF combination and a serum test only were ≤ 19% in 95% of simulations. The largest increases occurred when serum titers were from 40 to 160 and pre-test probabilities were from 5% to 60%. In all simulations, the difference between pre- and post-test probabilities was greater for a CSF test only, compared with a serum test only. Conclusions and clinical relevance - CSF testing after a serum test has limited usefulness in the diagnosis of EPM. A CSF test alone might be used when CSF is required for other procedures. Ruling out other causes of neurologic disease reduces the necessity of additional EPM testing.
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UR - http://www.scopus.com/inward/citedby.url?scp=33744495993&partnerID=8YFLogxK
U2 - 10.2460/ajvr.67.5.869
DO - 10.2460/ajvr.67.5.869
M3 - Article
C2 - 16649923
AN - SCOPUS:33744495993
VL - 67
SP - 869
EP - 876
JO - American Journal of Veterinary Research
JF - American Journal of Veterinary Research
SN - 0002-9645
IS - 5
ER -