The IKDT conducts diagnostic tests in strict adherence to FDA guidelines to detect inflammatory processes or viral infections in human myocardial biopsies. The diagnostic methods used include histology, immunohistochemical analysis, and PCR assays to detect viral genomes. Myocardial biopsies in their native or fixed form are preferred for these tests, and it's crucial that the submitted material undergoes a well-defined pre-analytical treatment to yield accurate results.
For endomyocardial biopsies, RNAlater is recommended for preservation at ambient temperature. This aqueous, non-toxic tissue storage reagent stabilizes and protects cellular RNA in intact, unfrozen tissue samples. With RNAlater, there's no need for immediate processing or freezing of the tissue samples in liquid nitrogen. It's also suitable for genomic DNA preparation, histological examination, and immunohistochemistry. Tissue samples can be harvested and submerged in RNAlater for storage without compromising the quality or quantity of RNA obtained after subsequent RNA isolation. RNAlater can also be added to cell pellets and cells in medium, and samples can be stored frozen or unfrozen.
To use RNAlater, endomyocardial biopsies measuring less than 0.5 cm in any one dimension should be simply submerged in approximately 500 µm of RNAlater at room temperature. The solution permeates the cells and stabilizes the RNA. Samples should be sent directly to the IKDT lab at ambient temperature or stored at +4°C before transport. Transportation can be done in a padded envelope by conventional mail. Upon arrival at the IKDT lab, the sample will be stored at +4°C overnight and then can be stored at 4°C for up to a month, at 25°C for up to a week, or at -20 to -80°C indefinitely.
Never treat the biopsies by other fixatives before RNAlater fixation!
RNAlater is only suitable for very small tissue samples (biopsies). Larger piece (explanted heart samples) has to be divided rapidly in small aliquots or should be cryo-conserved in liquid nitrogen.