The cardiac isoform of troponin I is a reliable biomarker of damaged cardiomyocytes that accompanies such severe cardiovascular diseases as myocardial infarction. Monoclonal antibody 19C7 recognizes troponin I in the blood-stream with high affinity and specificity. Recombinant antibodies can be used to improve detection systems based on monoclonal antibodies produced with hybridoma technology. In the present study, we compare the properties of monoclonal anti-body 19C7 and its recombinant fragments. It is shown that the recombinant antibody fragments demonstrate similar affinity values as monoclonal antibodies and can be applied for troponin I detection.