The utility of activated partial thromboplastin time (aPTT) clot waveform analysis in the investigation of hemophilia A patients with very low levels of factor VIII activity (FVIII:C).

The lower detection limit of the conventional one-stage aPTT based clotting assay for determining FVIII:C levels is generally 1.0-2.0 IU/dl. Consequently, it has been impossible to study the clinical significance of levels of FVIII:C less than 1.0 IU/dl. Using a photo-optical automated coagulation analyzer, the Organon Teknika MDA II, we have performed qualitative and quantitative aPTT waveform analysis and measured FVIII:C levels by automated one-stage aPTT clotting assay in 36 severely affected Hemophilia A patients. Qualitative waveform analysis showed clear evidence of individual differences in the waveform profile suggesting differing coagulant activity from patient to patient. The FVIII:C level was less than 0.2 IU/dl in 23 cases and levels of FVIII:C between 0.2 and 1.0 IU/dl could be discriminated in 13 patients. The FVIII:C level in these patients was closely correlated with the minimum value of the second derivative of the aPTT waveform (Min2). This is a measure of the acceleration of change in optical transmission at the initiation of coagulation. Furthermore, the correlation of the

Early identification of sepsis and mortality risks through simple, rapid clot-waveform analysis. Implications of lipoprotein-complexed C reactive protein formation.

OBJECTIVE: To determine if the rapid waveform profile of the activated partial thromboplastin time (aPTT) assay, which detects lipoprotein-complexed C reactive protein (LCCRP) formation, predicts sepsis and mortality in critically ill patients. DESIGN: Observational, cohort study. SETTING: General intensive therapy unit (ITU) of a tertiary care hospital. PATIENTS AND PARTICIPANTS: A total of 1187 consecutive patients admitted to the ITU. INTERVENTION: Activated partial thromboplastin time transmittance waveform analysis was performed within the first hour of admission to the ITU. The degree of change causing a biphasic waveform was quantified through the drop in light transmittance level. MEASUREMENTS AND RESULTS: Three hundred forty-six patients had a biphasic waveform on admission to the ITU with a mortality rate of 44% compared with 26% for those with normal waveforms. Logistic regression models showed direct correlation between the likelihood for sepsis and in-patient mortality with increasing waveform abnormalities. The mortality fraction was 0.3 with normal waveforms versus 0.6 when the light transmittance decreased by 30%. The odds ratio (OR) for mortality and sepsis were 4.5 and 11, respectively, from the most abnormal to normal aPTT waveforms. These were comparable with APACHE II scores and superior to those estimated by CRP for mortality (OR 2.3) / sepsis (OR 6.4) prediction. CONCLUSION: Waveform analysis within the first hour of ITU admission is a single, simple and rapid method of identifying the risks of mortality and sepsis. Its measure of LCCRP formation shows superior prediction over CRP alone and it warrants further assessment as a tool to triage and target prompt, appropriate treatment in the ITU.