The aim of this study was to establish the impact of air transport on blood samples packaged with and without cooling elements and effect of outdoor temperature on sample quality. Venous samples from 38 blood donors in winter and 36 in summer were tested for hemolysis and complete blood count. One tube per subject was kept in controlled conditions at +4 degreesC. Two sets of tubes were sent by plane from Zagreb to Brussels, one with and one without cooling elements, and another two sets were sent to London following the same principle. Packages with cooling elements were stored in controlled warehousing conditions at airports (+2 degreesC to +8 degreesC), whereas packages without cooling elements were stored in ambient warehouse conditions. Data loggers were used for temperature monitoring. Our research revealed statistically significant differences in several hematologic parameters when comparing the samples stored in controlled laboratory conditions and those transported by plane. These differences were more pronounced in the samples transported during the summer. Transport conditions without cooling elements had additional negative impact on the sample quality. Transport of samples using cooling elements and controlled warehousing conditions at airports are sometimes not sufficient to maintain laboratory storage conditions. Key words: Blood sample quality; Transport conditions; Hematologic parameters Cilj ovog istrazivanja bio je utvrditi utjecaj zracnog prijevoza na uzorke krvi pakirane s rashladnim elemenatima i bez njih, kao i utjecaj vanjske temperature na kvalitetu uzorka. U venskim uzorcima 38 darivatelja krvi tijekom zime i njih 36 tijekom ljeta odredeni su stupanj hemolize i kompletna krvna slika. Jedan uzorak po ispitaniku ostavljen je u kontroliranim uvjetima na +4 degreesC. Dva seta uzoraka poslana su zrakoplovom iz Zagreba u Bruxelles, jedan s rashladnim elemenatima i jedan bez njih, a druga dva seta poslana su u London po istom nacelu. Pakovanja s rashladnim elementima cuvana su u kontroliranim skladisnim uvjetima u zracnim lukama (+2 degreesC do +8 degreesC), dok su pakovanja bez rashladnih elemenata cuvana u ambijentnim skladisnim uvjetima. Uredaji za kontinuirano mjerenje temperature koristeni su za nadzor temperature tijekom transporta. Nase istrazivanje otkrilo je statisticki znacajne razlike u nekoliko hematoloskih parametara kada se usporeduju uzorci pohranjeni u kontroliranim laboratorijskim uvjetima i oni koji se transportiraju zracnim prijevozom. Te su razlike bile izrazenije u uzorcima transportiranim tijekom ljeta. Uvjeti transporta bez rashladnih elemenata imali su dodatni negativni utjecaj na kvalitetu uzoraka. Transport uzoraka pomocu rashladnih elemenata i kontrolirani uvjeti skladistenja u zracnim lukama ponekad nisu dovoljni za odrzavanje laboratorijskih uvjeta skladistenja. Kljucne rijeci: Kvaliteta uzoraka krvi; Uvjeti transporta; Hematoloski parametri