Dirofilaria immitis (heartworm) antigen testing is routinely performed in veterinary practices to detect canine heartworm infections. The purpose of this study was to evaluate the performance of two in-clinic assays to detect heartworm antigen on field samples from practices in heartworm endemic regions. Veterinary staff in 3 practices located in the Southern United States performed a side by side comparison of the SNAP® 4Dx® Plus Test (IDEXX) and the VETSCAN FLEX4® Test (Zoetis) on samples from canine patients presented for vector-borne disease screening. Assays were performed according to the manufacturer’s instructions. The remaining plasma sample was submitted for confirmatory testing using the PetChek® Heartworm Test (IDEXX) including immune complex dissociation (ICD) by heat treatment. A total of 232 samples were evaluated by the two in-clinic assays and PetChek Test. SNAP 4Dx Plus was significantly more sensitive for the detection of heartworm antigen in this study; sensitivity was 97.4 % for the SNAP 4Dx Plus test and 76.9 % for VETSCAN FLEX4 test (p < 0.01). The specificity of both tests was 99.5 %. This study reveals significant difference in detecting canine heartworm antigen in field samples.

丝虫病（心丝虫）抗原测试通常在兽医实践中进行，以检测犬心丝虫感染。这项研究的目的是评估两种临床检测方法的性能，这些检测方法可从心丝虫流行地区的实践中检测现场样本上的心丝虫抗原。位于美国南部的3个诊所的兽医人员对SNAP®4Dx®Plus测试（IDEXX）和VETSCANFLEX4®Test（Zoetis）进行了并列比较，结果显示来自犬病的病媒，用于病媒传播疾病筛查。根据制造商的说明进行测定。使用PetChek®蠕虫测试（IDEXX）将剩余的血浆样品提交进行确认测试，该测试包括通过热处理的免疫复合物解离（ICD）。通过两个临床检验和PetChek测试评估了总共232个样品。在这项研究中，SNAP 4Dx Plus对检测丝虫抗原的敏感性更高。SNAP 4Dx Plus测试的灵敏度为97.4％，VETSCAN FLEX4测试的灵敏度为76.9％（p <0.01）。两种测试的特异性均为99.5％。这项研究揭示了在野外样品中检测犬心丝虫抗原的显着差异。