Appropriateness of troponin testing in emergency department at a tertiary care hospital in Saudi Arabia

Discussion

In this study, half of the troponin tests ordered in the ED were inappropriate. This is consistent with the findings of similar studies published from the Western countries. There are several studies, audits and assessments of appropriateness of troponin testing that revealed 23-46% of requested troponin tests to be inappropriate.^3,4,12-14 In one such study, Abusalma et al³ found that 41.8% of the Tn I tests were requested inappropriately. The study was followed up after some educational intervention which resulted in the reduction of inappropriate testing of troponin almost by half compared to earlier numbers.³ Furthermore, clinical audits from United Kingdom and Ireland assessing the appropriateness of troponin testing for a period of one and 2 weeks showed that the proportion of inappropriate troponin ordering was 28.1% for a period of one week and 46% for 2 weeks.¹¹ A retrospective study from an Australian teaching hospital showed that 23.4% of troponin tests requested in the ED were deemed inappropriate as they were not in agreement with the clinical guidelines and did not alter the patient management.⁴

Published report shows that troponin assays are routinely performed in EDs even in the absence of clear clinical suspicion for ACS.⁴ A study from a large teaching hospital in Oxford where 40% of the troponin tests were ordered inappropriately showed that in addition to patient harm and over utilization of hospital resources, the cost of inappropriate tests amounted to 320£ over a period of just 48 hours.¹²

In our study, single troponin orders were used more extensively and inappropriately compared to serial orders. This is similar to what has been observed by Davey’s¹⁴ audit in 3 Australian hospitals where it was shown that majority of the single troponin orders were used more than the serial orders. In this study, there were 5 orders that were classified as inappropriate based on our pre-determined criteria that turned out to be positive for troponin. Upon analysis of these cases, we found that amongst 5 patients: 2 had bacteremia/sepsis, 2 were diagnosed with end stage renal disease (ESRD), and one had history of meningioma. It has been shown that troponin can be elevated in some non-cardiac conditions as well and there is a significant correlation between ESRD and troponin elevation.⁵ Similarly, there is a strong association between sepsis and elevated troponin levels as some studies have shown that elevated TnI or TnT can occur in up to 43-85% of patients with sepsis, however, no possible explanation can be attributed to the last case.^4,5

Our study revealed that out of 201 serial troponin orders, the initial test was appropriate in 17% (n=35) of the orders, but the repeated tests were inappropriate and 15% (n=30) of tests were initially ordered as well as repeated unnecessarily without any appropriate indication. Despite the relatively small number of these cases, the overall financial burden is much higher than anticipated because improper patient management may result in additional investigations, a longer length of stay, unnecessary treatment, and, most importantly, additional costs. Therefore, the importance of having an institutional protocol for appropriate test ordering and adherence to the test ordering guidelines cannot be emphasized more.

Reducing inappropriate ordering of troponin tests can generate huge financial benefits.^3,4 In our hospital, the cost of a single troponin test is 300 SAR and approximately 4000 troponin tests are ordered monthly from ED. This implies that nearly 1.2 million SAR are spent each month on troponin testing for ED alone. Based on our findings, 45% of these troponin orders could be inappropriate, resulting in a monthly expenditure of more than half a million SAR (0.54 million SAR) on inappropriate troponin orders from the ED. This equates to an estimated 6.48 million SAR that can be potentially saved annually. In fact, this is only a fraction of the total cost that can be saved because it excludes the overall cost, which includes prolonged length of stay, additional testing, delay in patient management, manpower, and time spent on such cases.

Detailed investigative study is required to explore the reasons for ordering inappropriate troponin tests in an acute care setting in the ED. Some of the plausible reasons could be over estimation of MI diagnosis by the physician, absence of a clear protocol for ordering troponin tests, ordering of tests by nurses or junior physicians in the triage area before examination of patients by senior physicians, or reckless ordering of a set of lab tests as a default for patients presenting in the ED (habit of click/tick the box practice).

In conclusion, clinical practices that support ordering of appropriate tests play a critical role in diagnosis, patient care, and proper resource utilization. Many strategies can be formulated to address this issue including creation of institutional protocols and clinical practice guidelines, conducting audits to assess test utilization, multidisciplinary collaborations, and adopting newer concepts in laboratory medicine like establishing diagnostic management teams, and initiating clinical laboratory stewardship programs. These initiatives could yield positive results through effective communication between clinical laboratory staff and physicians ordering the tests, commitment and support from hospital administration together with efficient project management and information technology support. Such firm understanding is crucial for good laboratory practices, improved patient outcomes, and appropriate utilization of healthcare resources.