Study designs of evaluations included in the review
No inclusion criteria relating to the study design were specified. All but one of the included studies was observational (prospective or retrospective series).
Specific interventions included in the review
Studies that measured the prothrombin time (PT) or international normalised ratio (INR) before an invasive procedure were eligible for inclusion. An abnormal test result was defined as an elevated INR or prolonged PT; where reported, the included studies defined an elevated INR as >1.2 or >1.5 and definitions of prolonged PT ranged from >11.5 seconds to >16 seconds.
Reference standard test against which the new test was compared
The review did not include any diagnostic accuracy studies that compared the performance of the index tests with a reference standard of diagnosis. The included studies measured the ability of the index tests to predict a clinical outcome.
Participants included in the review
Studies of participants undergoing one of 11 specified, invasive procedures were eligible for inclusion. Such procedures were: liver or kidney biopsy, nephrostomy tube placement, transhepatic biliary tube placement, epidural injection or lumbar puncture, central vein cannulation or implantation of venous access device, angiography or venography or cardiac catheterisation, thoracocentesis or paracentesis, or endoscopy. The included studies had to include at least 5 participants with abnormal test results. Participants were excluded if attempts were made to correct the coagulation abnormality prior to the procedure.
Outcomes assessed in the review
The included studies were required to report bleeding as an outcome, and report the outcomes separately for participants with abnormal coagulation tests. Definitions of bleeding and degree of severity varied between studies and were reported in full.
How were decisions on the relevance of primary studies made?
One reviewer made initial decisions on the relevance of primary studies using an abstract review form. More detailed inclusion criteria were then applied to retrieve articles.