Validated technologies for the collection, transport and processing of blood samples for in vitro diagnostic testing of genomic DNA, cell-free DNA, and intracellular RNA. As we noted in our previous publication of results of the first SPIDIA EQA of intracellular RNA, the inherent instability of RNA makes planning a well-controlled, external evaluation of this analyte in blood a considerable challenge. While results of the first EQA demonstrated an NVP-BEZ235 supply association between gene expression levels and RNA integrity number, the results did not indicate significant differences in the expression levels of the investigated genes as a function of storage time, temperature, or whether or not the blood collection tube contained an RNA stabilizer. The first EQA was conducted using pooled blood specimens from different donors collected in citrate phosphate dextrose adenine anti-coagulant. Pooled blood was aliquoted into proficiency specimens and shipped to participating laboratories under uncontrolled shipping conditions. These factors may have caused ex vivo changes in expression of investigated genes before RNA analysis. Since most blood specimens are collected in EDTA tubes, blood collection for the second study was performed using bags prefilled with an EDTA solution such that the final molar concentration approximated that of EDTA tubes. This step was taken to obtain a large volume of whole blood which closely resembled in composition whole blood specimens received in clinical laboratories, i.e. EDTA whole blood. Because blood from a single donor was not of sufficient volume to provide proficiency specimens to all study participants, two blood donors were enrolled, blood from each donor was aliquoted into T0 control and proficiency specimens, the resultant specimens were identified as to donor source, and the results segregated accordingly. The participating laboratories were therefore randomized into two groups, each group receiving proficiency specimens associated with one donor. To maintain constant temperature during sample shipment, we adopted dedicated shipping containers that maintained an internal temperature of 2uC to 8uC for 48 h. The protocol for participants for the second EQA was virtually the same as for the first EQA study. Briefly, two proficiency specimens, both either with or without an RNA stabilizing additive, were sent to participating laboratories according to whether or not they wished to receive tubes containing stabilizer. Participants were asked to extract the RNA from whole blood sample from one tube immediately after receipt by the laboratory and from the second tube 24 h later after storage at either ambient or refrigerated temperature. Storage temperature was assigned randomly. The participants were instructed to extract the RNA using their routine laboratory procedure and send the purified RNA samples back to the SPIDIA facility for analysis. The quality and quantity of RNA in the returned samples were evaluated by means of the same methodology used in the first SPIDIA-RNA EQA.