Silva Vanessa M, Rezende Denise C, Garcia Edna S, Cavalheiro Cyrillo, Strunz Celia C
Clinical Laboratory Instituto do Coracao, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil.
Hematology Outpatient Unit - Instituto do Coracao, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil.
Pract Lab Med. 2020 Oct 17;22:e00177. doi: 10.1016/j.plabm.2020.e00177. eCollection 2020 Nov.
The recommendations for adjustment of citrate volume in sample tubes with high hematocrit (Ht) are based on indirect studies of underfilled tubes or artificially constructed Ht values. The aim of this study was to evaluate the effect of citrate volume adjustment in sample tubes from patients with hematocrit >55% using two different prothrombin time (PT) tests.
Paired citrate-adjusted and unadjusted blood specimens were obtained from 181 patients from the pulmonary hypertension ambulatory with high Ht values and on warfarin therapy. The samples were tested using recombinant human tissue factor (RTF) and reagents extracted from rabbit brain (HS Plus). The results are expressed as the international normalized ratio (INR). The correlation and percent change (% change) between sample pairs were calculated.
INR-RTF results from adjusted and unadjusted citrate blood specimens showed a strong correlation ( = 0.8226, p < 0.0001). The INR median was 2.25 (95% CI 2.10 to 2.41) for citrate-adjusted samples and was 2.22 (95% CI 2.06 to 2.38) for citrate-unadjusted samples. For samples with Ht >62%, the % change between sample pairs was >10%. Results using HS Plus showed a moderate correlation between citrate-adjusted and unadjusted samples ( = 0.4267, p < 0.0001). The INR median was 2.51 (95% CI 2.35 to 2.68) for citrate-adjusted samples and 3.45 (95% CI 3.11 to 3.80) for citrate-unadjusted samples. For samples with Ht>55%, the % change between sample pairs was higher than 10%.
Our data demonstrate that in patients with polycythemia on warfarin therapy, INR-RTF does not require anticoagulant adjustment for assessment of samples with Ht <62%.
关于调整高血细胞比容（Ht）样本管中枸橼酸盐体积的建议是基于对未充满管或人工构建的Ht值的间接研究。本研究的目的是使用两种不同的凝血酶原时间（PT）测试评估在血细胞比容>55%的患者的样本管中调整枸橼酸盐体积的效果。
从181例患有肺动脉高压且血细胞比容值高并接受华法林治疗的门诊患者中获取配对的经枸橼酸盐调整和未调整的血液样本。使用重组人组织因子（RTF）和从兔脑提取的试剂（HS Plus）对样本进行检测。结果以国际标准化比值（INR）表示。计算样本对之间的相关性和百分比变化（%变化）。
经枸橼酸盐调整和未调整的枸橼酸盐血液样本的INR-RTF结果显示出强相关性（r = 0.8226，p < 0.0001）。经枸橼酸盐调整的样本的INR中位数为2.25（95%CI 2.10至2.41），未调整的样本为2.22（95%CI 2.06至2.38）。对于血细胞比容>62%的样本，样本对之间的%变化>10%。使用HS Plus的结果显示经枸橼酸盐调整和未调整的样本之间存在中度相关性（r = 0.4267，p < 0.0001）。经枸橼酸盐调整的样本的INR中位数为2.51（95%CI 2.35至2.68），未调整的样本为3.45（95%CI 3.11至3.80）。对于血细胞比容>55%的样本，样本对之间的%变化高于10%。
我们的数据表明，在接受华法林治疗的红细胞增多症患者中，对于评估血细胞比容<62%的样本，INR-RTF不需要调整抗凝剂。
