Blood serum stability limit and maximum storage time of bovine samples

Measuring metabolic parameters in the blood has been an indispensable tool for assessing the productive and health status of dairy cows for more than 100 years. The values of laboratory parameters depend on various preanalytical, analytical and postanalytical factors. The most important preanalytical factors are sample transport time and temperature, hemolysis, anticoagulant type, and sample volume. Preanalytical factors can lead to reduced stability of the analyte in the sample, which changes their concentration. Loss of stability changes the time of storage and manipulation of the sample, which determines the criteria for its acceptance or rejection. The two stability indicators are stability limit and maximum permissible instability. A stability limit (SL) is defined as the period of time in which a property variation does not exceed a maximum permissible instability (MPI). The aim of this study was to determine the SL and MPI for each analyte in the blood serum of cows and to determine whether SL differs in the function of the presence of preanalytical errors in the blood sample. Three hundred samples of dairy cow origin in different periods of lactation participated in this research. They were classified into 6 groups of 50 samples: according to the time from sampling to processing in the laboratory (0-4 h, 4-8 h and over 8 h; all transported on dry ice, protected from environmental factors, without preanalytical errors) and according to the presence of preanalytical errors (group with hemolysis, a group transported at ambient temperature and a group with a small sample volume). Each sample was aliquoted in two portions. One portion was left at +4°C and tested once a day for 6 days of sample storage, and the second portion, placed at -20°C, was tested once a month for 6 months. The MPI had a value ranging from 1.51 to 8.4. Metabolic profile analytes with lower MPI values (1.51-3.22) were albumin (ALB), total protein (TPROT), UREA, glucose (GLU), calcium (Ca), and phosphorus (P). Higher MPI values (5.1-8.4) were found for nonesterified fatty acids (NEFA), beta-hydroxybutirate (BHB), cholesterol (CHOL), triglycerides (TGC), total bilirubin (TBIL) and aspartat aminotransferase (AST). For most parameters, we can conclude that their PD% changed faster in storage conditions at +4°C compared to the regime of -20°C. The largest number of biochemical analytes in bovine blood serum shows preserved stability in the first 6 days at +4°C or 6 months at -20°C if transported to the laboratory within 8 h after sampling in ideal conditions and without the action of preanalytical errors. Prolonged transport under ideal conditions or the existence of preanalytical errors such as transport at room temperature, hemolysis or small sample volume shorten the stability of the ALB, NEFA, GLU, UREA and P. Concentration of all analytes decreases during the stability test except for UREA, NEFA, BHB and for CHOL and TGC in some groups. Variations in parameters such as BHB, NEFA, TBIL, AST, and Ca have shown potential clinical significance. At storage conditions at +4°C, clinically significant variations at at least one measurement point were found for AST (7.5% of samples), BHB (6.1% of samples), NEFA (9.9% of samples) and for TBIL (in 7% of samples). This study can help define acceptable delay times and storage conditions for bovine blood samples, which is of great importance because in working with farm animals it is often not possible to take samples in a short time and deliver them to the laboratory, and samples are often burdened with certain preanalytical errors with limited possibilities of re-sampling.(AU)

Parâmetros bioquímicos e hemogasométricos do sangue total canino armazenado em bolsas plásticas contendo CPDA-1 e CPD/SAG-M / Parameter biochemical and hemogasometric of the total blood stored of dogs in plastic stock markets I contend CPDA-1 and CPD/SAG-M

O presente trabalho teve como objetivo avaliar e comparar as alterações bioquímicas e hemogasométricas do sangue total canino armazenado em bolsas CPDA-1 e CPD/SAG-M. Foram utilizados 14 cães machos, adultos e saudáveis, distribuídos em dois grupos com sete animais cada, dos quais foi obtido sangue para o estudo. No primeiro grupo (G1), o sangue foi armazenado em bolsas CPDA-1 e, no segundo grupo (G2), o sangue foi armazenado em bolsas CPD/SAG-M. As amostras foram analisadas para: potássio, sódio, glicose, proteína plasmática total, DPG, pH sangüíneo, pO2 , pCO2 e bicarbonato. Os momentos estabelecidos para as análises laboratoriais foram: D0: imediatamente após a coleta do sangue dos animais; D7: sete dias após a coleta; D14: quatorze dias após a coleta; D21: vinte e um dias após a coleta; D31: trinta e um dias após a coleta; D41: quarenta e um dias após coleta. A análise dos resultados permitiu concluir que a bolsa CPD/SAG-M apresentou melhor desempenho quando comparada à CPDA-1 após 41 dias de estocagem. O DPG, mesmo com pH inferior a sete, continua sendo produzido por, pelo menos, uma semana após a estocagem do sangue na bolsa.

The present study was aimed at evaluating and comparing the biochemical and haemogasometrics alterations of the total blood of dogs stored in bags CPDA-1 and CPD/SAG-M. 14 male's dogs, adult and healthful dogs, were divided in two groups, which one blood was removed for the study. The blood of the first group (G1) was stored in bag CPDA-1 and that of the second group (G2) in bag CPD/SAG-M. The samples were analyzed for: potassium, sodium, glucose, total plasmatic protein, DPG, pH, pO2 , pCO2 , and bicarbonate. The moments for the laboratory analyses were established: D0: immediately after the collection of blood; D7: seven days after the collection; D14: fourteen days after the collection; D21: twenty and one days after the collection; D31: thirty and one days after the collection; D41: forty one days after collect. The evaluation of the results allowed including that: the bag CPD/SAG-M presented advantage when compared with the CPDA-1 after 41 days of stored. The DPG, even with pH lower then 7, continues being produced for, at least, one week after the stocking of the blood in the bag.

Tempo de viabilidade de amostras de sangue venoso bovino destinadas ao exame hemogasométrico, quando mantidas sob conservaçäo em água gelada / Viability time of blood gas analysis in bovine venous blood samples stored in ice water bath

Com o objetivo de verificar o tempo de viabilidade de amostras de sangue venoso bovino destinadas ao exame hemogasométrico, quando conservadas em banho de água gelada, selecionaram-se 14 bovinos (7 machos e 7 fêmeas), clinicamente sadios, entre 1 e 5 anos de idade. Colheram-se, de cada animal, 2 amostras de sangue(10ml cada), por punçäo da veia jugular, com o emprego de seringas plásticas contendo cerca de 1.000UI de heparina sódica, tomando-se os cuidados de eliminar quaisquer bolhas de gás presentes, e de manter vedada a extremidade da agulha com rolha de borracha. Cada uma do par de seringas foi mantida, distintamente, à temperatura ambiente (entre 23 e 30§C) ou submersa em água gelada (entre zero e 4§C). As determinaçöes do pH, pressöes parciais venosas de dióxido de carbono (PvCO2)e de oxigênio (PvO2), bicarbonato (HCO3), total de dióxido de carbono (TCO2), excesso ou déficit de bases (BE), bicarbonato padräo (StB), saturaçäo de oxigênio (SatO2) e do conteúdo de oxigênio (O2) foram realizadas imediatamente e com 1, 2, 3, 4, 5, 6, 8, 10, 12 e 24 horas após a colheita. Em cada um dos critérios de manutençäo do material, os resultados foram avaliados por meio da análise de variância de medidas repetidas. Consideradas as diferenças entre os valores médios obtidos em cada tempo e aquele da avaliaçäo inicial, os resultados indicaram que as alteraçöes "in vitro" das amostras näo conservadas já eram marcantes a partir de 2 ou 3 horas, caracterizando-se por reduçöes contínuas do pH, PvO2, BE, StB, Sat O2 e O2, e por elevaçäo gradativa da PvCO2. No sangue conservado, ao contrário, o valor de pH näo exibiu diferença do original durante as primeiras 4 horas, e os de PvCO2, BE e StB mantiveram-se inalterados por até 6 horas após a colheita. A análise dos resultados permitiu concluir que as amostras de sangue venoso bovino destinadas ao exame de hemogasometria podem permanecer viáveis por até 6 horas, quando adequadamente conservadas em banho de água gelada, mantendo, assim, o seu valor diagnóstico.