RECOMMENDATIONS FOR USE OF POINT-OF- CARE TROPONIN ASSAYS IN ASSESSMENT OF ACUTE CORONARY SYNDROME

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1 RECOMMENDATIONS FOR USE OF POINT-OF- CARE TROPONIN ASSAYS IN ASSESSMENT OF ACUTE CORONARY SYNDROME Dr Philip Tideman on behalf of Troponin Working Party

2 Troponin PoCT Working Party Louise Cullen (ACEM) Rita Horvath (RCPA) Gus Koerbin (AACB) Cameron Martin (AACB) Paul Simpson (AACB) Fernando SanGil (AACB) Jill Tate (AACB) Philip Tideman (CSANZ) Rosy Tirimacco (AACB)

3 Why have a PoCT Troponin Working Party Concern raised that with the introduction of high sensitive Trop tests POC Trop tests were being used outside of their scope Appropriate sampling times not used

4 Clinical Recommendations -1 Troponin results should be interpreted in the clinical context. Biomarkers are only one piece of information to be used along with an ECG and clinical picture for risk stratification according to clinical guidelines Elevated Trops aren t always due to ACS Low results from early presenters don t always rule out ACS

5 Clinical Recommendations -2 Serial troponin measurements should be performed for all patients presenting with symptoms suggestive of ACS, unless the patient has been reliably ACS symptom free for 24 hours Clear justification why no second sample 0 hour determined from first blood draw not onset of symptoms Recommended timings at presentation and 2 nd 6-8 hrs post presentation

6 Clinical Recommendations -3 Serial testing should be performed using the same troponin assay and platform. Examples scenarios to avoid: Troponin I done at presentation but second location uses troponin T assay PoC troponin I done at presentation but second location uses laboratory troponin I assay * PoC troponin T done at presentation but second location uses laboratory troponin T assay* *exception is where PoC and laboratory assays are shown to be comparable

7 Clinical Recommendations -4 Serial measurements help to compensate for an increased troponin equivocal zone at the 99 th percentile although PoC assays are less accurate than laboratory troponin assays Quantitative troponin delta change has not been determined for use with PoC assays due to assay inaccuracy at low troponin concentration When a central laboratory is used, results should be available as soon as possible, with a goal of within 60 minutes. Otherwise PoC testing should be considered

8 Analytical Recommendations It is important to recognise the limitation of PoC troponin vs. laboratory troponin in terms of analytical performance which impacts clinical performance Troponin PoC assays are analytically less sensitive for the detection of the troponin molecule and less accurate compared with high sensitive and sensitive assays used by laboratories; however, generally PoC assays are guideline acceptable based on a scorecard performance approach

9 Scorecard Performance Approach Apple FS. A new season for cardiac troponin assays: it s time to keep a scorecard. Clin Chem 2009; 55:

10 Sample Collection, Handling and Troponin Testing Testing should only be performed by operators who are accredited and within a quality framework False negative and false positive troponin results due to micro-clots and haemolysis originate most commonly in the Emergency Department

11 Sample Collection, Handling and Troponin Testing-1 A general approach to reducing micro-clots is: Mix blood tubes immediately after collection to avoid formation of micro-clots that may not be visible on testing but which can cause falsely low troponin values

12 Sample Collection, Handling and Troponin Testing -2 Avoid haemolysed samples by: Use of trained collectors Do not collect blood from the site of insertion of an intravenous cannula Do not use very fine bore needles

13 Causes of Elevated Cardiac Troponins Acute Myocardial Infarction Tachy or bradyarrythmias Aortic dissection or severe aortic valve disease Severe hypo or hypertension, e.g. haemorrhagic shock, hypertensive emergency Acute or chronic heart failure Hypertrophic cardiomyopathy Coronary vasculitis, e.g. SLE, Kawasaki synd. Severe pulmonary embolism or pulmonary hypertension Dialysis dependent renal failure Cardiac Contusion or surgery Rhabdomyolysis with cardiac involvement Myocarditis, severe sepsis Cardiotoxic agents, e.g. anthracyclines, CO poisoning Severe burns affecting >30% body surface Severe acute neurological conditions, e.g. stroke, trauma Infiltrative diseases, e.g. amyloidosis, sarcoidiosis Extreme exertion, e.g. marathon running Frequent defibrillator shocks Coronary artery spasm, e.g. cocaine

14 Suggested Pathways

15 Radiometer AQT90 Troponin T iccnet and NSW Health Pathology

16 Radiometer AQT90 Troponin I

17 Cobas h232 Troponin T

18 Abbott i-stat Troponin I TnI on presentation (Time 1) >0.04 µg/l 0.04 µg/l Repeat i-stat TnI: Collect second sample at 3-6 hours after presentation (Time 2) High-risk stratification TnI >0.04 µg/l WITH a typical rise and/or fall of TnI. Change (Delta TnI) : TnI {Time 2 Time 1} is 0.02 µg/l at 0.10 µg/l, or >20% at >0.10 µg/l No AMI not likely High risk for AMI Yes Clinical assessment and further TnI testing if AMI suspected