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I am sorry to hear about this situation. If the lab made a mistake, then yes, they can be sued for negligence. The elements of a negligence cause of action are (1) The defendant owed a legal duty to the plaintiff, (2) The defendant breached that duty, and (3) The breach was a proximate cause of the plaintiff's personal injury or property damages. D. Houston, Inc. v. Love, 92 S.W.3d 450, 454 (Tex.2002).
As such, if the lab made a mistake and this mistake is later proven, then the lab may be liable for the legal/attorney fees it cost to fix the mistake, for example.
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