Implementation of an early rule-out pathway for myocardial infarction using a high-sensitivity cardiac troponin T assay.

OBJECTIVES: Patients with suspected acute coronary syndrome and high-sensitivity cardiac troponin (hs-cTn) concentrations below the limit of detection at presentation are low risk. We aim to determine whether implementing this approach facilitates the safe early discharge of patients. METHODS: In a prospective single-centre cohort study, consecutive patients with suspected acute coronary syndrome were included before (standard care) and after (intervention) implementation of an early rule-out pathway. During standard care, myocardial infarction was ruled out if hs-cTnT concentrations were <99th centile (14 ng/L) at presentation and at 6-12 hours after symptom onset. In the intervention, patients were ruled out if hs-cTnT concentrations were <5 ng/L at presentation and symptoms present for ≥3 hours or were ≥5 ng/L and unchanged within the reference range at 3 hours. We compared duration of stay (efficacy) and all-cause death at 1 year (safety) before and after implementation. RESULTS: We included 10 315 consecutive patients (64±16 years, 46% women) with 6642 (64%) and 3673 (36%) in the standard care and intervention groups, respectively. Duration of stay was reduced from 534 (IQR, 220-2279) to 390 (IQR, 218-1910) min (p<0.001) after implementation. At 1 year, all-cause death occurred in 10.9% (721 of 6642) and 10.4% (381 of 3673) of patients in the standard care group (referent) and intervention group, respectively (adjusted OR 1.02, 95% CI 0.88 to 1.18). CONCLUSION: In patients with suspected acute coronary syndrome, implementing an early rule-out pathway using hs-cTnT concentrations <5 ng/L at presentation reduced the duration of stay in hospital without compromising safety.

The value of serum free light chains in a case of Waldenstrom's macroglobulinaemia that produces a type I cryoglobulinaemia.

Lymphoplasmacytic lymphoma (Waldenstrom's macroglobulinaemia) is a low-grade small-cell lymphoma that produces monoclonal IgM. Usually, clinical features are related to growth of the tumour and include weakness and fatigue, an increased bleeding tendency, and neurological and visual disturbances. We present a case of lymphoplasmacytic lymphoma with type I cryoglobulinaemia that presented with clinical symptoms associated with hyperviscosity syndrome. Quantitation of the paraprotein was not possible using conventional serum protein electrophoresis due to the high serum viscosity, and therefore monitoring was carried out using serial serum free light chain measurements.

Serum free light chains; the need to establish local reference intervals.

BACKGROUND: The purpose of this study was to compare The Binding Site serum free light chain assay on two analytical platforms; the Dade Behring BNII and the Olympus AU400. Reference intervals were subsequently established on each analyser. METHODS: In total, 112 serum samples routinely submitted to the laboratory for protein electrophoresis were used for the comparison study. Reference interval data was generated from 126 ostensibly healthy anonymous individuals. RESULTS: Serum free light chain results on the BNII and AU400 analysers are not directly comparable. The BNII produces results which are significantly higher than the AU400. CONCLUSIONS: Laboratories using The Binding Site serum free light chain assay are strongly advised to establish local reference intervals.