probable clinical diagnosis临床疑诊？

The CDC criteria for probable clinical diagnosis include all of the following:

• Single or multiple painful genital ulcers 

• No evidence to support a diagnosis of syphilis (no evidence of T. pallidum infection by darkfield examination or ulcer exudate or by a serologic test for syphilis performed at least 7 days after onset of ulcers) 

• Appearance of the ulcer and, if present, regional lymphadenopathy that are typical for chancroid

• A negative test (HSV PCR test or HSV culture) for the presence of HSV in the ulcer exudate

美国疾病控制中心（Centers for Disease Control，CDC）的临床疑诊标准包括以下所有内容：

l 一个或多个痛性生殖器溃疡

l 没有证据支持梅毒的诊断（通过暗视野检查、溃疡渗出物或溃疡发生后至少7天进行的梅毒血清学测试，无梅毒螺旋体感染证据）

l 软下疳典型的溃疡和（如果有的话）局部淋巴结病

l 溃疡渗出物中单纯疱疹病毒试验阴性（HSV PCR检查或HSV培养）

probable clinical diagnosis 临床疑诊？

at least 7 days 至少7天？啥意思？连做七天检查？

谢谢