activated partial thromboplastin timethromboplastin timecauses of high prothrombin timepartial thromboplastin time rangepartial thromboplastin time testpartial thromboplastinincreased prothrombin time causesactivated thromboplastin timelow partial thromboplastin timepartial prothromboplastin timepart thromboplastin timepartial thromboplastin time blood test