Influence of the sampling technique on the measurement of peritoneal fibrinolytic activity.

Objective: To establish the influence of the peritoneal sampling technique on the measurement of fibrinolytic capacity.

Design: Clinical study.

Setting: University hospital, Germany.

Subjects: 40 peritoneal biopsy specimens were taken from 10 patients who were having elective colorectal resections.

Interventions: Peritoneal biopsy specimens were taken either with a biopsy punch (n = 20) or manually with forceps and scissors (n = 20).

Main outcome measures: Extent of agreement in fibrinolytic activities between specimens taken with biopsy punch and manually. Major endpoint-peritoneal tissue plasminogen activator (t-PA) activity. Minor endpoints-peritoneal tissue plasminogen activator concentration, and concentration and activity of plasminogen activator inhibitior type 1 (PAT-1).

Results: Intra-assay agreement and the extent of agreement between the groups were evaluated by the method of Bland and Altman. Correlation of repeated measurements of t-PA and PAI-1 concentrations and activities from the same sample using the same ELISA kit was high (r = 0.93-0.99, p < 0.01). t-PA activities and concentrations between the groups correlated poorly (r= 0.60 and 0.66, p < 0.01) while no correlation at all was seen for PAI-1 concentration and activity between the groups (r = 0.6 and 0.1, p = 0.2 and 0.9). The mean differences between the groups ranged from -27% to -4.8%.

Conclusion: The sampling technique considerably affects the measurement of peritoneal fibrinolytic activity.