Adcock D M, Kressin D C, Marlar R A
Department of Pathology, Colorado Permanente Medical Group, University of Colorado Health Sciences Center, Denver, USA.
Am J Clin Pathol. 1998 May;109(5):595-9. doi: 10.1093/ajcp/109.5.595.
We evaluated the effect of sample volume and citrate concentration on results of routine coagulation assays (prothrombin time [PT] and activated partial thromboplastin time [APTT]). The study was performed on samples obtained from healthy persons and patients receiving oral anticoagulant therapy. Standard evacuated tubes (3.2% and 3.8% sodium citrate) were filled to varying total sample volumes ranging from 3.0 to 5.0 mL, and results of routine coagulation tests were compared. Underfilling may significantly affect the APTT and PT, resulting in artifactual prolongation of results. This effect is most pronounced in samples drawn into 3.8% citrate. By using 3.8% citrate, there is a statistically significant difference in the results of PT assays in the samples less than 80% filled compared with those that are 100% filled. For APTT assays performed on samples drawn into 3.8% citrate, a statistical difference occurred at less than 90% filled. This effect was less pronounced when samples were drawn into 3.2% sodium citrate. We found no statistically significant difference in PT results from a 3.2% citrate tube between fill volumes of 60% and 100% and none for APTT results between fill volumes of 70% and 100%. This study further supports the recommendation to use 3.2% sodium citrate concentration, because 60% of the optimum filled volume for PT and 70% of the optimum filled volume for APTT are acceptable.
我们评估了样本量和枸橼酸盐浓度对常规凝血试验（凝血酶原时间[PT]和活化部分凝血活酶时间[APTT]）结果的影响。该研究对从健康人以及接受口服抗凝治疗的患者获取的样本进行。将标准真空采血管（3.2%和3.8%枸橼酸钠）填充至3.0至5.0 mL不等的总样本量，并比较常规凝血试验的结果。采血量不足可能会显著影响APTT和PT，导致结果出现人为延长。这种影响在采集到3.8%枸橼酸盐的样本中最为明显。使用3.8%枸橼酸盐时，与100%采血量的样本相比，采血量低于80%的样本PT测定结果存在统计学显著差异。对于采集到3.8%枸橼酸盐的样本进行的APTT测定，采血量低于90%时出现统计学差异。当样本采集到3.2%枸橼酸钠中时，这种影响不太明显。我们发现，3.2%枸橼酸盐采血管中，采血量在60%至100%之间时，PT结果无统计学显著差异；采血量在70%至100%之间时，APTT结果也无统计学显著差异。本研究进一步支持使用3.2%枸橼酸钠浓度的建议，因为PT的最佳采血量的60%和APTT的最佳采血量的70%是可接受的。
