title: Importance of preanalytical handling of samples for measurement of cardiac troponin T in coronary effluent from isolated rat hearts.
abstract: The isolated, buffer-perfused heart is probably the most widely used model in experimental heart research, and the coronary effluent is often analysed for markers of myocardial injury. Adsorption to surrounding materials may be a serious problem of protein measurements in solutions with low protein concentrations. The aims of the present study were to investigate the importance of the preanalytical phase when measuring cardiac troponin T (cTnT) in a buffer perfusate and to investigate whether addition of albumin to the effluent might increase recovery of cTnT and improve the assay. Coronary effluent was collected in tubes of different materials and in tubes with 40 g/L bovine albumin, and then frozen. cTnT was analysed at different time points after withdrawal from the freezer. cTnT was 2.3-119 times higher in effluent with albumin. In effluent without albumin, cTnT concentration declined to 2% of the initial concentration after two episodes of freezing and thawing. The cTnT loss could not be prevented by using polystyrene or siliconized glass, but was partially inhibited in effluent with albumin. Furthermore, creatine kinase and lactate dehydrogenase levels were higher in effluent with albumin. The within-series coefficient of variation for cTnT was markedly improved when using effluent with albumin.
authors.affiliation: Department of Clinical Chemistry, Huddinge University Hospital, Stockholm, Sweden. christian.lowbeer@chemlab.hs.sll.se
authors.forename: C
authors.initials: C
authors.lastname: Löwbeer
authors.forename: T
authors.initials: T
authors.lastname: Kawakami
authors.forename: P
authors.initials: P
authors.lastname: Tähepĵld
authors.forename: S A
authors.initials: SA
authors.lastname: Gustafsson
authors.forename: J
authors.initials: J
authors.lastname: Vaage
authors.forename: G
authors.initials: G
authors.lastname: Valen
mesh_terms: D000327:Adsorption; D000818:Animals; D015415:Biomarkers; D002021:Buffers; D003402:Creatine Kinase / Q000378:metabolism; D005615:Freezing; D066298:In Vitro Techniques; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D017202:Myocardial Ischemia / Q000175:diagnosis; D009206:Myocardium / Q000737:chemistry* / Q000201:enzymology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012710:Serum Albumin, Bovine / Q000494:pharmacology; D013048:Specimen Handling / Q000379:methods* / Q000592:standards; D020107:Troponin T / Q000032:analysis*
chemical_list: D015415:Biomarkers; D002021:Buffers; D020107:Troponin T; D012710:Serum Albumin, Bovine; D007770:L-Lactate Dehydrogenase; D003402:Creatine Kinase