The Sinai Troponin

    NextPrevious

    The Sinai Troponin

    What is Sinai’s troponin assay? Answer: ARCHITECT STAT Troponin-I

    A Global Task Force with involvement from the American Heart Association (AHA), American College of Cardiology Foundation (ACCF), European Society of Cardiology (ESC), and World Heart Federation (WHF) agreed on a universal definition of myocardial infarction that supports use of cTnI as a preferred biomarker for myocardial injury.

    Elevated levels of cardiac TnI are detectable in serum within 4-6 hours after the onset of chest pain with peak in approximately 8-28 hours. It may remain elevated for 3- 10 days after an MI.

    The ARCHITECT STAT Troponin-I assay analytical sensitivity is ≤ 0.01 ng/mL (≤ 0.01 μg/L) at the 95% level of confidence. The ARCHITECT STAT Troponin-I assay analytical specificity is ≤ 0.1% crossreactivity with skeletal troponin-I and ≤ 1% with cardiac troponin-C and cardiac troponin-T.

    A study was performed that had compared 13 commonly troponin assays. Of note, the assay at Sinai is not a high sensitivity troponin-I (hsTnI) assay. While the limit of detection for the regular stat TnI is 0.01, that for the hsTnI is 0.001. Abbott iSTAT (different from the STAT Sinai has) and Ortho cTnI assays were two of the assays that more frequently had negative reads when all others were grossly positive aka be glad we don’t have these. Another study compared the ARCHITECT STAT TnI vs hsTnI. It showed the advantage of using the hsTnI to be in populations that appear with chest pain 1-3 hours after onset. Serial sampling using hsTnI can be reduced from 6-9 hours after the initial to 3 hours because it’s level of detection (LoD) was >50% of normals. Being able to more confidently do a repeat troponin 3 hours from the first as opposed to what would be 6 hours from with the regular STAT TnI would improve flow through an Emergency Department. Also, while the regular TnI assays take about 6 hours to diagnose an acute NSTEMI in terms of laboratory findings, the hsTnI assays cut that time more confidently to 3 hours and possibly as low as 1 hour in about 70% of patients with chest pain. The positive predictive value of the hsTnI goes from 75.1% to 95.8% after 3 hours. The first approved high sensitivity assay was approved in 2017 by the FDA despite being available in other parts of the world for years.

    Shout-out to Sam Khan for requesting this topic as a TR pearl.

    Resources:

    http://jalm.aaccjnls.org/content/jalm/early/2017/02/10/jalm.2016.022640.full.pdf

    https://www.corelaboratory.abbott/sal/whitePaper/CR_ADD-00001076_ARCHITECT_hsTnI_WhitePaper_072613.pdf

    https://www.sciencedirect.com/science/article/pii/S0019483216001140

    Troponin Insert

    https://i.pinimg.com/originals/7e/8b/f2/7e8bf2704380a27b844f36d3b0ca7f7a.jpg

    • Welcome! This is the website for the Mount Sinai Emergency Ultrasound Division. It serves as an information resource for residents, fellows, medical students and others seeking information about point-of-care ultrasound. There is a lot ofRead more

    • renal handling of water

      If you were on a tea & toast diet, how much water would you need to drink before you develop hyponatremia? I haven’t seen anyone work out the numbers before so here are my calculations. AndRead more

    • acute acidemia physiology

      As alluded to in the first post, don’t be fooled by a “normal” potassium in the setting of DKA because osmotic diuresis and H+/K+ exchange means that total body potassium is actually LOW. You all knowRead more

    • renal handling of potassium

      the first symptom of hyperkalemia is death Earlier post covered temporizing measures to counter hyperkalemia — namely, intracellular shift, increasing cardiac myocyte threshold potential. Give furosemide if the patient still urinates and consider dialysis, but then askRead more

    • bicarbonate revisited

      Previous post reviewed the safety of balanced crystalloids in hyper K. But what was up with serum bicarbonate decreasing with saline administration? This post introduces a new way of looking at the anion gap to possiblyRead more

    • hyperkalemia and balanced crystalloids

      Is it safe to give LR or plasmalyte to a hyperkalemic patient (these balanced crystalloids have 4-5 mEq/L K as opposed to 0 mEq/L K in normal saline)? Postponing the discussion of renal handling of potassium toRead more

    • hyperkalemia physiology

      You’ll likely encounter hyperkalemia on your next Resus / Cardiac shift, and you’ll instinctively treat it. But take a moment to review the fascinating physiology behind the “cocktail”! First, consider how K+ is buffered byRead more

    • Slow down your tachycardia (but not really)

      You’re sitting in resus bemoaning the departure of your most beloved attending when suddenly a patient wheels in without warning. The patient looks relatively stable but the triage RN tells you her heart rate wasRead more

    • Otitis externa: use the ear wick!

      Acute otitis externa (AOE) is a common complaint seen in pediatric as well as adult emergency departments. AOE is typically not accompanied by acute otitis media, although concurrent cases are possible. Also called “swimmer’s ear”Read more

    NextPrevious