Abstract：
OBJECTIVE: To determine the sensitivity and specificity of a commercial whole blood real-time PCR assay (RT-PCR) for the diagnosis of histoplasmosis when compared to direct organism identification and/or urine antigen quantification by enzyme immunoassay (UA-EIA). A secondary objective was to compare the sensitivity and specificity of RT-PCR to anti-Histoplasma immunoglobulin G antibody detection by enzyme immunoassay (IgG-EIA) and IgG-EIA to UA-EIA.
METHODS: Cats presented to the Kansas State University Veterinary Health Center from February through September of 2023 in which histoplasmosis was diagnosed or suspected.
METHODS: From February through September of 2023, cats were tested by RT-PCR, IgG-EIA, and UA-EIA if histoplasmosis was diagnosed cytologically or was a differential diagnosis for the presenting clinical signs. Cats were excluded if all 3 tests were not submitted or if the diagnosis of histoplasmosis could not be excluded despite a negative UA-EIA result. Cats with cytologically or histologically confirmed histoplasmosis were designated as proven histoplasmosis cases, and cats with a positive UA-EIA result without cytological or histological confirmation were designated as probable histoplasmosis cases.
UNASSIGNED: 10 cats were diagnosed with either proven (n = 6) or probable (4) histoplasmosis, and 10 cats were considered true negatives. Whole blood RT-PCR results were negative in all 20 cats (sensitivity, 0%; 95% CI, 0% to 30.85%). The IgG-EIA was 90% sensitive (95% CI, 55.50% to 99.75%) and 70% specific (95% CI, 34.75% to 93.33%). The UA-EIA results were positive in all cats with proven histoplasmosis.
CONCLUSIONS: This commercial RT-PCR is insensitive when used on whole blood collected in EDTA and should not be used to diagnose feline histoplasmosis. Further studies are required to determine whether alternate RT-PCR protocols for EDTA-collected whole blood could be useful for diagnosing histoplasmosis in cats.
METHODS: Cats presented to the Kansas State University Veterinary Health Center from February through September of 2023 in which histoplasmosis was diagnosed or suspected.
METHODS: From February through September of 2023, cats were tested by RT-PCR, IgG-EIA, and UA-EIA if histoplasmosis was diagnosed cytologically or was a differential diagnosis for the presenting clinical signs. Cats were excluded if all 3 tests were not submitted or if the diagnosis of histoplasmosis could not be excluded despite a negative UA-EIA result. Cats with cytologically or histologically confirmed histoplasmosis were designated as proven histoplasmosis cases, and cats with a positive UA-EIA result without cytological or histological confirmation were designated as probable histoplasmosis cases.
UNASSIGNED: 10 cats were diagnosed with either proven (n = 6) or probable (4) histoplasmosis, and 10 cats were considered true negatives. Whole blood RT-PCR results were negative in all 20 cats (sensitivity, 0%; 95% CI, 0% to 30.85%). The IgG-EIA was 90% sensitive (95% CI, 55.50% to 99.75%) and 70% specific (95% CI, 34.75% to 93.33%). The UA-EIA results were positive in all cats with proven histoplasmosis.
CONCLUSIONS: This commercial RT-PCR is insensitive when used on whole blood collected in EDTA and should not be used to diagnose feline histoplasmosis. Further studies are required to determine whether alternate RT-PCR protocols for EDTA-collected whole blood could be useful for diagnosing histoplasmosis in cats.
摘要：
目的：与直接生物鉴定和/或通过酶免疫测定（UA-EIA）进行尿液抗原定量相比，确定商业全血实时PCR检测（RT-PCR）诊断组织胞浆菌病的敏感性和特异性。第二个目的是比较RT-PCR对酶免疫测定（IgG-EIA）和IgG-EIA对UA-EIA的抗组织胞浆免疫球蛋白G抗体检测的敏感性和特异性。
方法：猫从2023年2月到9月被送到堪萨斯州立大学兽医健康中心，在该中心被诊断或怀疑为组织胞浆菌病。
方法：从2023年2月到9月，对猫进行了RT-PCR检测，IgG-EIA,和UA-EIA，如果组织胞浆菌病是细胞学诊断的，或者是表现出临床体征的鉴别诊断。如果未提交所有3项检查，或者尽管UA-EIA结果为阴性，但仍不能排除组织胞浆菌病的诊断，则排除猫。经细胞学或组织学证实的组织胞浆菌病的猫被指定为已证实的组织胞浆菌病病例。UA-EIA结果阳性而无细胞学或组织学证实的猫被指定为可能的组织胞浆菌病病例。
■10只猫被诊断为已证实的（n=6）或可能的（4）组织胞浆菌病，10只猫被认为是真正的阴性。20只猫的全血RT-PCR结果均为阴性（敏感性，0%；95%CI，0%至30.85%）。IgG-EIA为90%敏感性(95%CI,55.50%至99.75%)和70%特异性(95%CI,34.75%至93.33%)。在所有已证实的组织胞浆菌病的猫中，UA-EIA结果均为阳性。
结论：这种商业RT-PCR在用于EDTA中收集的全血时不敏感，不应用于诊断猫组织胞浆菌病。需要进一步的研究来确定EDTA收集的全血的替代RT-PCR方案是否可用于诊断猫的组织胞浆菌病。
方法：猫从2023年2月到9月被送到堪萨斯州立大学兽医健康中心，在该中心被诊断或怀疑为组织胞浆菌病。
方法：从2023年2月到9月，对猫进行了RT-PCR检测，IgG-EIA,和UA-EIA，如果组织胞浆菌病是细胞学诊断的，或者是表现出临床体征的鉴别诊断。如果未提交所有3项检查，或者尽管UA-EIA结果为阴性，但仍不能排除组织胞浆菌病的诊断，则排除猫。经细胞学或组织学证实的组织胞浆菌病的猫被指定为已证实的组织胞浆菌病病例。UA-EIA结果阳性而无细胞学或组织学证实的猫被指定为可能的组织胞浆菌病病例。
■10只猫被诊断为已证实的（n=6）或可能的（4）组织胞浆菌病，10只猫被认为是真正的阴性。20只猫的全血RT-PCR结果均为阴性（敏感性，0%；95%CI，0%至30.85%）。IgG-EIA为90%敏感性(95%CI,55.50%至99.75%)和70%特异性(95%CI,34.75%至93.33%)。在所有已证实的组织胞浆菌病的猫中，UA-EIA结果均为阳性。
结论：这种商业RT-PCR在用于EDTA中收集的全血时不敏感，不应用于诊断猫组织胞浆菌病。需要进一步的研究来确定EDTA收集的全血的替代RT-PCR方案是否可用于诊断猫的组织胞浆菌病。
