BackgroundErrors associated with failures in filing, actioning and communicating blood test results can lead to delayed and missed diagnoses and patient harm. This study aimed to audit how blood tests in primary care are filed, actioned and communicated in primary care, to identify areas for patient safety improvements.MethodsUK primary care clinicians were recruited through the Primary Care Academic CollaboraTive (PACT). PACT members audited 50 recent sets of blood tests from their practice and retrospectively extracted data on blood test result coding, actioning and communication. PACT members received a practice report, showing their own results, benchmarked against other participating practices.ResultsPACT members from 57 general practices across all four UK nations collected data on 2572 patients who had blood tests in April 2021. In 89.9% (n=2311) they agreed with the initial clinician’s actioning of blood tests; 10.1% disagreed, either partially (7.1%) or fully (3.0%).In 44% of patients (n=1132) an action (eg, ‘make an appointment’) was specified by the filing clinician. This action was carried out in 89.7% (n=1015/1132) of cases; in 6.8% (n=77) the action was not carried out, in 3.5% (n=40) it was unclear. In the 117 cases where the test result had not been actioned 38% (n=45) were felt to be at low risk of harm, 1.7% (n=2) were at high risk of harm, 0.85% (n=1) came to harm.Overall, in 47% (n=1210) of patients there was no evidence in the electronic health records that results had been communicated. Out of 1176 patients with one or more abnormal results there was no evidence of test communication in 30.6% (n=360). There were large variations between practices in rates of actioning and communicating tests.ConclusionThis research demonstrates variation in the way blood test results are actioned and communicated, with important patient safety implications.