miR-21
rnamiR-21 is elevated during acute MI, promoting platelet activation and aggregation while amplifying cardiomyocyte injury responses.
Pathway placement
Cascade stepPlatelet adhesion & activation
Confidencehigh
RationaleUpregulated in STEMI; platelet activation and aggregation; early MI dysregulation.
Also acts inMyocardial injury
Druggability
Not assessed (no mapped human gene target).
Type I vs Type II discrimination
ScoresLow-confidence (proxy)
R — rupture / Type-I51
C — confounder / Type-II87
A — assay feasibility50
E — evidence strength32
T1DI (composite)5
Specificity differential (R−C)-36.2
Confounder panel (Type-II drivers)
No confounder evidence retrieved.
Tier: light (literature co-occurrence proxy — lower confidence). See the discrimination table for all markers.
Assay & specimen
Class-level default (no specific cleared assay)— generic method inferred from analyte class; confirm against a specific product insert before use.
Specimen
Whole blood or cell-free plasma
Collection tube
PAXgene/Tempus RNA tube · K2/K3-EDTA (lavender-top)
Method / principle
RT-qPCR (TaqMan) or small-RNA sequencing
Reagent / substrate
Target-specific primers/probe; reverse transcriptase (miRNA: stem-loop RT primer)
Platform
qPCR instrument / NGS
Turnaround · availability
Research / send-out · Research (few LDTs)
Literature evidence(4)
- An exploration into the diagnostic capabilities of microRNAs for myocardial infarction using machine learning.Biology direct · 2024 · PMID 39658789 · doi
- Circulatory miR-133b and miR-21 as Novel Biomarkers in Early Prediction and Diagnosis of Coronary Artery Disease.Genes · 2020 · PMID 32033332 · doi
- Platelet microRNA for predicting acute myocardial infarction.Journal of thrombosis and thrombolysis · 2017 · PMID 29030746 · doi
- Plasma microRNA-21 is a potential diagnostic biomarker of acute myocardial infarction.European review for medical and pharmacological sciences · 2016 · PMID 26875904