Patent ID: 8756974

Claim:
A breath alcohol tester, comprising: a breath manifold designed to accept breath from a human subject, said breath including an early breath followed by a later breath; a flow restriction, wherein an action of said breath in said breath manifold against said flow restriction creates a positive pressure in said breath manifold; a fuel cell; and a sampling system, the sampling system comprising an electrochemical volume-displacement device; wherein said manifold is configured to use said positive pressure in said manifold to force at least a portion of said early breath into said fuel cell via backpressure without said sampling system sampling said early breath; wherein the amount of alcohol forced into said fuel cell by said early breath is measured by said fuel cell as a first value; wherein at least a portion of said later breath is displaced by said sampling system and provided to said fuel cell; wherein the amount of alcohol in the portion at said later breath displaced by said sampling system is measured by said fuel cell as a second value; and wherein if a ratio of said first value to said second value is above a predetermined threshold said breath alcohol tester disregards said second value.