Immunoassays | Toxicity | Cardiovascular

Erenna® Cardiac Troponin-I Immunoassay Kit (Cat# 03-0019-xx)

Introduction

The Erenna® cTnI Immunoassay Kit uses a quantitative fluorescent sandwich immunoassay technique to measure cTnI in plasma and serum samples. A capture antibody specific for cTnI has been pre-coated onto paramagnetic microparticles (MP). The user pipettes MP, standards, and samples into uncoated microplate wells. During incubation, the cTnI present in the sample binds to the capture antibody on the coated MP. Unbound molecules are washed away during the subsequent buffer exchange and wash steps. Fluor-labeled detection antibody is added to each well and incubated. This detection antibody recognizes and binds to cTnI that has been captured onto the MP. During the following wash step the MPs are transferred to a clean plate. Elution buffer is then added and incubated. The elution buffer dissociates the bound protein sandwich from the MP surface, releasing the labeled antibodies. These antibodies are separated during transfer to a final microplate. The plate is loaded into the Erenna System where the labeled molecules are detected and counted. The number of fluor-labeled detection antibodies counted is directly proportional to the amount of cTnI present in the sample when captured. The amount of cTnI in unknown samples is interpolated from a standard curve.

Assay Performance

TABLE 1. Analytical sensitivity of the Erenna® Cardiac Troponin-I Immunoassay Kit¹
Lower Limit of Detection	0.1 pg/mL
Lower Limit of Quantification²	0.4 pg/mL
Upper Limit of Quantification	600 pg/mL
Low-end CV% Range	2 - 8%
Low-end CV% Average	5%
Recommended Sample Volume	50 μL
Minimum Sample Volume Required³	20 μL

¹ See product insert for updated values
² LLoQ = 20% CV and ± 20% recovery
³ based upon median [cTnI] in a healthy reference

FIGURE 1. [cTnI] in EDTA plasma from 20 healthy donors, with median and interquartile range. Erenna® cTnI Immunoassay Kit reliably quantifies cTnI in healthy subjects, who have a median [cTnI] of 1.1 pg/mL that is well above the detection limit of 0.1 pg/mL.

FIGURE 2. Erenna® cTnI Immunoassay Kit low-end standard curve signal (left) and curve fit (right).

Representative data shown for demonstration purposes only. Individual results may vary depending upon samples tested and protocol used.

Biology and Disease

Cardiac Troponin-I (cTnI) is specifi c to cardiomyocytes and is released into blood following heart damage. Extensive studies have shown that cTnI is slowly released from damaged cardiomyocytes. Measurement of cTnI concentrations in plasma are the standard of care for diagnosing non-STEMI acute myocardial infarction (AMI). In addition, this biomarker has been widely accepted in preclinical and clinical drug development settings as an indicator of myocardial damage and hence, heart damage.

TABLE 2. Additional UniProtKB/Swiss-Prot Information*
Protein Name:	Troponin I, cardiac muscle
UniProtKB/Swiss-Prot ID:	P19429
Protein-protein interaction database:	P19429
Alternative Names:	Cardiac troponin I
Gene Names:	TNNI3
Synonym Gene Names:	TNNC1
Function:	Troponin I is the inhibitory subunit of troponin, the thin filament regulatory complex which confers calcium-sensitivity to striated muscle actomyosin ATPase activity.
Biological Processes:	cardiac muscle contraction, cellular calcium ion homeostasis, negative regulation of ATPase activity, vasculogenesis
Molecular Function:	actin binding, calcium channel inhibitor activity, calcium-dependent protein binding

* Source Info from www.uniprot.org.

Erenna® Cardiac Troponin-I Immunoassay Kit (Cat# 03-0019-xx)

Introduction

Assay Performance

Biology and Disease

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