High-Sensitivity Cardiac Troponin I Levels Below 99th Percentile Upper Reference Limit in Patients Presenting with Suspicion of Acute Coronary Syndrome (ACS) in Emergency Department at a Tertiary Care Hospital in Karachi, Pakistan.

INTRODUCTION: Troponin I levels are biomarkers of choice for diagnosis of acute myocardial infarction (AMI). However, prognostic significance of values below the 99th percentile upper reference limit (URL) in patients presenting with symptoms suggestive of Acute coronary syndrome (ACS) need further evaluation. AIM: The objectives of the study were to find the association of High sensitivity (hs)-Troponin I values below 99th percentile URL with age and the Emergency Department (ED) outcome, to determine single cut-off for safe discharge of these patients from the ED and to determine the 30-day outcome of the patients admitted under cardiac speciality. METHODS: This is a retrospective study of patients presenting with suspicion of ACS in the ED between January 2019 till April 2021 and hs-Troponin I values below 99th percentile URL. RESULTS: Among 15,441 patients, 8034 (52%) were males and 7407 (48%) were females. 9677 (63%) of the patients had hs-Troponin I values < 5 ng/L while 5764 (37%) had values between 5 ng/L and 99th percentile URL. Higher hs-Troponin I values were associated with a worse ED outcome. Serial troponin I levels were performed in only 2.4% of the cohort. Receiver operating characteristics for ACS demonstrated an AUC of 0.84 at a cut off value of 12.75 ng/L, with sensitivity (76.9%) and specificity was 75.1%. The 30-day outcome of the patients admitted under cardiac speciality revealed no mortality in either group. CONCLUSION: An overall single cut-off value of 12.75 ng/L can be used in our population for ruling our ACS provided it is unaccompanied by other supportive clinical and ECG findings.

A wide spectrum of dengue IgM and PCR positivity post-onset of illness found in a large dengue 3 outbreak in Pakistan.

During a large outbreak of dengue serotype 3 in Pakistan in 2006, multiple serum samples were routinely collected for laboratory testing. Two hundred ninety-seven samples were collected between August and November 2006. Serological testing for dengue IgM was performed in Pakistan and polymerase chain reaction (PCR) testing for dengue RNA detection and serotyping were performed in Hong Kong. Dengue-specific IgM was detectable as early as 1 day, and dengue RNA remained detectable for up to 14 days, post-onset of illness. Further statistical analysis found that IgM status (positive, negative, or equivocal) was significantly correlated to clinical (duration of illness, severity of patient-reported arthralgia pain, the presence of any evidence of bleeding, a positive tourniquet test, shock), and other laboratory (platelet and total white cell counts) parameters. In contrast, the qualitative dengue RNA status (PCR positive or negative) was not statistically significantly correlated with any of these other parameters. The results for this population during this outbreak, obtained from single acute samples, demonstrate a wide range of intervals post-onset of illness during which dengue IgM and dengue RNA may be detected. Interestingly, in this study, the dengue IgM positivity correlates more closely with significant clinical illness than the dengue RNA positivity, which may be a feature specific to this particular outbreak.