Abstract
ContextLaboratory tests for inflammatory response, thyroid function and infectious diarrhoea were not being ordered as recommended by clinical guidelines.ObjectiveTo measure changes in community laboratory-test ordering following marketing programmes promoting guidelines recommendations.DesignControlled before-and-after study involving 2 years of national laboratory payment data before and after each intervention. Comparisons were with doctors ordering the same tests but not receiving interventions.SettingNew Zealand primary care.Participants3161, 3140 and 3335 general practitioners and 2424, 2443 and 2766 Comparison doctors ordering inflammatory response, thyroid function and acute diarrhoea tests from community laboratories, July 2003 to March 2009.InterventionsThree separate marketing programmes to general practitioners, each comprising written material advising of guidelines recommendations, individual laboratory-test use feedback and professional development opportunities.Main outcome measuresNumber of tests, tests/doctor, patients having tests and tested patients/doctor/year before and after each intervention. Change in expenditure from before each intervention to after.ResultsFor Intervention doctors, erythrocyte sedimentation rate tests decreased 60.0% after the intervention; tests for C-reactive protein increased 63.1%; simultaneous erythrocyte sedimentation rate and C-reactive protein orders decreased 32.6%. Tests for free thyroxine and free triiodothyronine decreased 44.1% and 36.0%. The proportion of thyroid function tests where thyroid-stimulating hormone was the sole test ordered increased from 43.2% before the intervention to 65.2% afterwards (p<0.001; 95% CI 21.7% to 22.2%). Testing for faecal culture decreased 31.5%, giardia and cryptosporidium 31.5%, and ova and parasites 56.9%. Faecal culture as the sole initial test increased from 31.4% to 39.1% (p<0.001; 95% CI 7.2% to 8.2%). Testing by Comparison doctors changed in the same direction but with significantly less magnitude. The estimated reduction in expenditure for study tests was 23.5%.ConclusionsClear information marketed to general practitioners improved the quality of laboratory test ordering for patients in New Zealand.