Lab studies HbCo analysis Elevated levels are significant; however low levels do not rule out exposure, especially if the patient already has received 100% oXygen or if significant time (8h) has elapsed since exposureLab Studies ◼ HbCO analysis – Elevated levels are significant; however, low levels do not rule out exposure, especially if the patient already has received 100% oxygen or if significant time (8h) has elapsed since exposure