A mixed acid-base disorder may be present (eg lactic acidosis from peripheral circulatory failure, or metabolic alkalosis from vomiting). An associated lactic acidosis may mask the presence of the ketoacidosis. This occurs because the lactic acidosis decreases the acetoacetate : beta-hydroxybutyrate ratio (ie more beta-hydroxybutyrate produced ) because NAD+ is produced in the production of lactate. The common test used to detect ketones (eg ‘Acetest’) depends on the reaction of acetoacetate (and to a lesser extent acetone) with the nitroprusside reagent. A decreased acetoacetate level may lead to a weak or absent test reaction despite high total levels of total ketoanions (acetoacetate and beta-hydroxybutyrate combined) because the beta-hydroxybutyrate is not detected.