Testing times ahead for the Irish healthcare system? A behaviour change intervention targeting test ordering in primary care

One of the most consistent findings in health services research relates to gaps between ideal (as determined by scientific evidence) and actual care. Shifting care out of hospitals and into the Primary Care, community setting is at the core of a plan to radically transform Irish healthcare. Under an expansion of Primary Care, community diagnostics would grow and treatment would be moved from the acute sector to the community sector.

Laboratory testing is a fundamental diagnostic tool for supporting medical decisions in Primary Care. It is essential for the screening, diagnosis and monitoring of disease, and thus indispensable in the practice of health care. However, demand for laboratory testing is increasing disproportionately to other medical activity, and the tests involved are becoming increasingly complex. In addition, the literature suggests that as much as 70% of laboratory tests may not be needed. Moreover, a laboratory test may be initiated for an estimated 30% of patient encounters in Primary Care. Promoting optimal laboratory service utilisation could play a key role in reducing health expenditure, in particular, by preventing the unnecessary use of costly downstream services that often arise as a result of testing.

Tackling ineffective test use in the South of Ireland: a case study using serum immunoglobulins

It is likely that wasteful requesting of laboratory tests occurs across all tests, and similarly across all disciplines of medicine. However, it was not feasible to examine all tests, and, for the purpose of this research we decided to explore requests for quantitative serum immunoglobulins.

Taking a systematic approach, and using a combination of behaviour change techniques we explored serum immunoglobulin testing among General Practitioners (GPs) in the South of Ireland. Serum immunoglobulin tests measure the level of immunoglobulins (antibodies), in the blood. Antibodies are proteins made by the immune system to defend against antigens, such as bacteria, viruses, and toxins. Quantitative serum immunoglobulin tests are used to detect abnormal levels. Low immunoglobulin levels characterise some antibody immunodeficiencies (when the immune system is not working properly). These are really rare. Meanwhile, high immunoglobulin levels (polyclonal gammopathy) are often found in liver diseases, chronic inflammatory diseases, haematological disorders, cancers and infections.

A systematic review of the literature identified a variety of interventions, including, audit and feedback and altering test ordering forms, which have shown varying levels of effectiveness. In particular, results varied by tests and the context of the health care system in which they were implemented. Using routine laboratory data for all GP requested serum immunoglobulin tests in the South of Ireland during 2013 (N=5,990), we identified some of the key physician and practice characteristics associated with higher test ordering. Identified characteristics included female gender and less medical experience (years since graduating with a medical degree). Interestingly, no associations were found between practice-level factors and immunoglobulin test ordering rates.

Using the results of the review and cross-sectional analysis of routine laboratory data, GP test ordering behaviours were explored in further detail through semi-structured interviews (N=16). The incorporation of behavioural theory, specifically the ‘capability’, ‘opportunity’, ‘motivation’ and ‘behaviour’ (COM-B) model, Theoretical Domains Framework (TDF) and Behaviour Change Theory (BCT) taxonomy, supported the identification of factors such as knowledge and the social and environmental context, which are key for understanding testing behaviours. Selected BCTs and intervention functions provided the groundwork for developing a theory-based intervention to improve appropriate immunoglobulin testing in Primary Care.

As a result, a combined guideline and educational messages intervention was designed (and implemented) based on the pooled findings of the above studies (cited below). The intervention provides guidelines on when to request the immunoglobulin tests. It also clearly communicates situations where testing is/is not beneficial for patient care and how to manage patients with abnormal immunoglobulin results. Finally, it provides details on how to interpret the results by electronically attaching comments to test reports. Using a segmented regression analysis of five years of routine laboratory data on all GP requests in the South of Ireland, this intervention was found to have a statistically significant 1.2% fortnight-to-fortnight reduction in the test ordering trend for serum immunoglobulins (after one year follow-up).

Health Policy implications

This study was designed to target the key issues around GP serum immunoglobulin test ordering behaviour. While modest, the financial benefits to the public health service in Ireland will be much larger if our intervention is applied to other settings and is found to work for other tests. At a policy level, the findings point to the possible benefits of laboratories becoming more actively engaged in GP education about test ordering. Any such engagement should seek to understand drivers of the GP behaviour first, and interventions should be jointly developed with GPs on the basis of sound behaviour change theory.


Dr Sharon Cadogan

Teaching Fellow in Epidemiology

Imperial College London


Email: s.cadogan@imperial.ac.uk


This research was funded by the Health Research Board PhD Scholars Programme.



  1. Cadogan, S.L., Browne, J.P., Bradley, C.P., & Cahill, M.R. (2015). The effectiveness of interventions to improve laboratory requesting patterns among primary care physicians: a systematic review. Implementation Science10(1), 167.


  1. Cadogan, S.L., McHugh, S.M., Bradley, C.P., Browne, J.P., & Cahill, M.R. (2016). General practitioner views on the determinants of test ordering: a theory-based qualitative approach to the development of an intervention to improve immunoglobulin requests in primary care. Implementation Science11(1), 102.


  1. Cadogan, S.L., Browne, J.P., Bradley, C.P., Fitzgerald, A.P., & Cahill, M.R. (2017). Physician and practice characteristics associated with immunoglobulin test ordering. Family Practice.


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