Unexpected positive lupus anticoagulant and isolated prolongation of aPTT following infection

As an uncommon cause, prolonged aPTT caused by lupus anticoagulant (LA) after infection is easily overlooked. Here, we describe two cases like this. A 3-year-old boy received many tests until dilute Russell’s viper venom time screening, mixing tests, and confirmatory tests were programed. Time and cost consuming, mental stress of the child and his parents were seen. After that, a 4-year-old girl was identified isolated prolonged aPTT at screening before adenotonsillectomy. Fortunately, she was quickly diagnosed. The two cases reveal the construction of the relationship among infection, LA and isolated prolonged aPTT plays a vital role in the clinic practice.