James K M, Polzin D J, Osborne C A, Olson J K
Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St Paul 55108, USA.
Am J Vet Res. 1997 Apr;58(4):343-7.
To determine whether underfilling blood collection tubes leads to in vitro reduction in serum measured total CO2 concentration ([TCO2]m) in canine and feline blood samples sufficient to create the impression of metabolic acidosis (pseudometabolic acidosis) or high anion gap.
Blood samples from healthy client-owned animals (16 dogs, 17 cats).
Venous blood samples were collected in random order for determination of serum [TCO2] and blood gas tensions. Blood gas analysis was performed on iced, capped blood samples. In dogs, serum [TCO2] was measured in 1-, 3-, and 10-ml samples in 10-ml type-B tubes and in a 3-ml sample in 3-ml type-A tubes. In cats, serum [TCO2] was determined in 1-, 2-, and 3-ml samples in 3-ml type-A tubes and in a 3-ml sample in 10-ml type-B tubes.
For dogs, serum [TCO2] in full-tube, 10-ml samples was a mean +/- SD, 2.0 +/- 1.1 mmol/L greater than that in 3-ml samples and 3.7 +/- 1.3 mmol/L greater than the value in 1-ml samples; both differences were significant at P < 0.0001. The serum [TCO2] in full 3-ml samples was lower by 0.4 +/- 0.6 mmol/L than the value in full-tube 10-ml samples (P = 0.019). For cats, serum [TCO2] in full-tube, 3-ml samples was 0.5 +/- 0.6 mmol/L greater than that in 2-ml samples (P = 0.004) and was 1.5 +/- 0.8 mmol/L greater than the value in 1-ml samples (P < 0.0001). Serum [TCO2] in 3-ml samples of feline blood in 10-ml tubes was 0.8 +/- 0.8 mmol/L lower than that in samples from full 3-ml tubes (P = 0.0007). In dogs and cats, [TCO2] in fully filled collection tubes was approximately 6 mmol/L higher when calculated from blood gas analysis data than when chemically determined in serum.
Underfilling blood collection tubes results in a false decrease in serum [TCO2], which can contribute in part to descrepancies between blood gas and chemical analyses as estimates of plasma bicarbonate concentration. This, and other in vitro effects of sample handling and collection, may result in a false assessment of metabolic acidosis in dogs and cats.
确定采血管采血不足是否会导致犬猫血液样本中测得的血清总二氧化碳浓度（[TCO2]m）在体外降低，从而足以造成代谢性酸中毒（假性代谢性酸中毒）或高阴离子间隙的假象。
来自健康客户拥有动物的血液样本（16只犬，17只猫）。
随机采集静脉血样本以测定血清[CO2]和血气张力。对冰冻、加盖的血样进行血气分析。在犬中，在10 ml B型管中分别取1 ml、3 ml和10 ml样本以及在3 ml A型管中取3 ml样本测定血清[CO2]。在猫中，在3 ml A型管中分别取1 ml、2 ml和3 ml样本以及在10 ml B型管中取3 ml样本测定血清[CO2]。
对于犬，全管10 ml样本中的血清[CO2]比3 ml样本中的平均高2.0±1.1 mmol/L，比1 ml样本中的值高3.7±1.3 mmol/L；两者差异均在P<0.0001时具有统计学意义。3 ml全量样本中的血清[CO2]比全管10 ml样本中的值低0.4±0.6 mmol/L（P = 0.019）。对于猫，全管3 ml样本中的血清[CO2]比2 ml样本中的高0.5±0.6 mmol/L（P = 0.004），比1 ml样本中的值高1.5±0.8 mmol/L（P<0.0001）。10 ml管中3 ml猫血样本中的血清[CO2]比3 ml全量管中的样本低0.8±0.8 mmol/L（P = 0.0007）。在犬和猫中，根据血气分析数据计算时，完全充满的采血管中的[CO2]比血清化学测定值高约6 mmol/L。
采血管采血不足会导致血清[CO2]假性降低，这可能部分导致血气分析和化学分析在估计血浆碳酸氢盐浓度时出现差异。这以及样本处理和采集的其他体外效应可能导致对犬猫代谢性酸中毒的错误评估。
