private void btnShowTestResults_Click(object sender, EventArgs e)
        {
            // get test results for patient
            Bundle results = client.Search <DiagnosticReport>(new string[]
            {
                $"patient={patient.Id}"
            });

            foreach (Bundle.EntryComponent entryComponent in results.Entry)
            {
                // add the DiagnosticReport to the list...
                DiagnosticReport report       = entryComponent.Resource as DiagnosticReport;
                string           testReportId = report.Id;
                string           test         =
                    report.GetExtension("http://wales.nhs.uk/fhir/extensions/DiagnosticReport-WrrsReportTitle").Value.ToString();
                string effectiveDate = ((FhirDateTime)report.Effective).ToDateTime().Value.ToString("dd-MMM-yyyy");
                string organisation  = "";
                DiagnosticReport.PerformerComponent firstOrDefault = report.Performer.FirstOrDefault();
                if (firstOrDefault != null)
                {
                    organisation = firstOrDefault.Actor.Display;
                }

                var lvi = new ListViewItem(testReportId);
                lvi.SubItems.Add(test);
                lvi.SubItems.Add(effectiveDate);
                lvi.SubItems.Add(organisation);
                lstTestResults.Items.Add(lvi);
            }
        }