PT、APTT检测的质量控制

在血栓与止血检验过程中，实验结果受到诸多因素的影响。为了对血栓与止血性疾病检测标准化，特别是血浆凝血酶原时间(Plasma Prothrombin Time，PT)、活化部分凝血活酶时间(Activated Partial Thromboplastin Time，APTT)检测的标准化，实验室质量控制显得特别重要。笔通过临床实践，有以下体会，供大家参考。     

影响检测凝血酶原时间和活化部分凝血活酶时间的因素分析

目的　探讨采血后室温放置不同时间和血液与抗凝剂不同比例对测定凝血酶原时间 (PT)、活化部分凝血活酶时间 (APTT)的影响。方法　抽取 4 0例体检健康者血液与抗凝剂 9∶1和 6∶1混匀 ,分离血浆后立即测定 ,另将 9∶1血浆分别于 1h、2h、4h、6h测定。结果　室温放置 4h和 6h检测结果与即刻测定相比PT、APTT时间均延长 ,PT有显著差异 (P <0 .0 5) ,APTT有极显著差异 ( P <0 .0 1) ;血液与抗凝剂比例缩小 ,PT和APTT时间延长 ( P <0 .0 5)。结论　检测PT、APTT应严格把握抗凝剂比例 ,标本采集后 2h以内检测完毕     

凝血酶原时间 活化部分凝血活酶时间对2型糖尿病患者血管并发症的临床意义

目的探讨2型糖尿病患者凝血酶原时间(PT)和活化部分凝血活酶时间(APTT)的变化及其临床意义。方法将试验对象分为3组:健康对照组;2型糖尿病无血管并发症组和有血管并发症组。用Sysmex CA 1500全自动凝血分析仪分别测定3组试验对象的PT、APTT;用Olympus AU 6400全自动生化仪测定其血糖及糖化血红蛋白(HbA1c)水平。结果 2型糖尿病患者有血管并发症者体内常有凝血功能障碍,其PT、APTT与健康对照组相比明显缩短,差异有统计学意义(P<0.01),并且PT、APTT的缩短与HbA1c水平呈负相关。无血管病变组与健康对照组比较差异无统计学意义。结论 2型糖尿病患者并发血管病变可能使患者PT、APTT缩短,且缩短水平与患者体内HbA1c呈负相关,监测2型糖尿病患者凝血功能有助于糖尿病患者并发微血管病变的早期诊断与监测。     

Routine use of the prothrombin and partial thromboplastin times

The prothrombin time (PT) and activated partial thromboplastin time (APTT) tests are often routinely ordered for hospitalized patients. Ordering patterns and clinical indications for the PT and APTT tests on the medical service at a teaching hospital were studied. Eighty-one percent of all patients admitted to the medical service had a PT and APTT test ordered. When compared with a modified version of guidelines for the use of the PT and APTT tests recently developed by the Medical Necessity Project of the Blue Cross and Blue Shield Associations of America and endorsed by the American College of Physicians, at least 70% of these tests were not clinically indicated. Many of the unindicated tests were ordered prior to invasive procedures or, apparently, out of habit. These inappropriate PT and APTT tests cost at least $60,948 per year for the medical service. Based on these findings, we suggest methods of reducing the inappropriate use of the PT and APTT tests.     

胆囊围手术期FBG、APTT、PT变化研究

目的:动态观察纤维蛋白原(FBG)、活化部分凝血活酶时间(APTT)及凝血酶原时间(PT)在围胆囊手术期的变化及机理。方法:将30例胆囊结石欲行胆囊切除术的患者分为术前、术中及术后即刻共3组,分别比较FBG、APTT、PT的变化。结果:纤维蛋白原术中与术前,术后与术中,术后与术前相比均呈阶段性减少,差异有统计学意义(P<0.01)。活化部分凝血活酶时间,术中与术前及术后比较差异均无统计学意义(均P>0.05),术后与术前比较差异有统计学意义(P<0.05)。凝血酶原时间的INR值,术前、术中、术后差异均无统计学意义(均P>0.05)。结论:纤维蛋白原可被麻醉及手术创伤所影响呈减少趋势,APTT不受麻醉影响,但可受手术创伤影响而致时间缩短。PT则不受手术及麻醉的影响。     

6种凝血活酶试剂测定凝血酶原时间评价

目的探讨不同来源的凝血活酶试剂对凝血酶原时间(PT)测定的影响.方法选择病人组40例及抗凝治疗组20例,在STA-Compact全自动凝血仪上采用配套试剂(R1)和其他5种不同ISI值的凝血活酶试剂(R2～6)测定PT,结果用SPSS10.0 for Windows 2000进行统计学处理.结果R1～R5测定PT的批内CV为1.15%～4.9%,R6为7.3%;R1和R2的批间CV分别为2.38%、3.45%,R3～R6为6.43%～8.10%;与R1测定结果相比较,R2～R6测定病人组PT的相关系数分别为0.992、0.912、0.940、0.600和0.120,其中R6测定PT有显著性差异(P＜0.05);当凝血酶原时间国际标准化比值(INR)＞2.0时,R3～R6测定抗凝治疗组的INR结果差异均有显著性意义(P＜0.05).加入33.3μmol/L胆红质、8.6mmol/L甘油三脂和0.62g/L血红蛋白对R2～R6测定PT均有显著性影响(P＜0.05).结论除该仪器配套试剂R1外,其它5种不同来源的凝血活酶试剂对测定结果均存在不同程度的差异.建议使用原装配套试剂与仪器组成标准的检测系统,有效确保PT测定结果的准确性和可靠性.     

How well does the activated partial thromboplastin time predict postoperative hemorrhage?

To determine the clinical usefulness of the activated partial thromboplastin time in screening patients before surgery, we related preoperative test results to the occurrence of hemorrhagic complications, studying all adult inpatients undergoing invasive diagnostic or therapeutic procedures at a large university hospital during a one-year period. Using clinical characteristics to divide the population into two groups according to a priori risk of hemorrhagic complications, we found that the activated partial thromboplastin time had no ability to predict the occurrence or absence of hemorrhage in the low-risk group, but that it was a predictor of modest strength in the high-risk group. Our data justify limiting preoperative coagulation screening to patients with active bleeding, known or clinically suspected bleeding disorders (including use of anticoagulants), liver disease, malabsorption, malnutrition, or other conditions associated with acquired coagulopathies and patients whose procedures may interfere with normal coagulation.     

纤维蛋白原、活化部分凝血活酶时间、凝血酶原时间、凝血酶时间、D-二聚体检测对评定肝硬化患者肝损伤程度的意义

目的:分析纤维蛋白原(FIB)、活化部分凝血活酶时间(APTT)、凝血酶原时间(PT)、凝血酶时间(TT)、D-二聚体的检测对评定肝硬化患者肝损伤程度的临床意义。方法:选取47例肝硬化患者作为甲组,再选取同期的健康成人47例为乙组,对两组患者的FIB、APTT、PT、TT、D-二聚体的水平进行分析对比。结果:甲组APTT、PT、TT、D-二聚体比乙组健康成人明显延长,FIB则明显下降,差异有统计学意义(P<0.05)。肝功能A、B、C级患者的APTT、PT、TT、D-二聚体依次延长,FIB则依次降低。三个级别中任何两级患者的FIB、APTT、PT、TT、D-二聚体检查结果比较,差异有统计学意义(P<0.05)。结论:对肝硬化患者进行凝血四项和D-二聚体检查,有利于早期发现肝病所造成的凝血机制障碍,能协助医生对肝脏受损程度进行准确评定.     

The effect of different nitrate preparations on plasma heparin concentrations and the activated partial thromboplastin time.

There is evidence that intravenous nitrates which are frequently used in acute coronary syndromes may interfere with the anticoagulant effect of heparin. We compared the effect of two different nitrate preparations on the activated partial thromboplastin time (APTT), anti-thrombin III activity (AT III) and plasma heparin levels in patients (n = 50) undergoing routine percutaneous transluminal coronary angioplasty (PTCA) for stable angina. Patients were randomized to either: (1) intravenous heparin and nitroglycerin (GTN); or (2) intravenous heparin and isosorbide dinitrate. The APTT, plasma heparin concentration and AT III activity were measured before PTCA and at 2 and 4 hours after commencement of infusions. Both groups received identical doses of heparin. Group 1 patients received a constant dose of 16.6 micrograms/minute of GTN, and group 2 patients received 33.3 micrograms/minute of isosorbide dinitrate. At 4 hours the median APTT ratio was significantly lower in group 1 compared with group 2 (2.6 versus 4.5) (P < 0.05) as was the plasma heparin concentration (0.18 U/ml versus 0.32 U/ml (P < 0.05). However, no significant difference in APTT ratios or plasma heparin concentrations were noted at any of the other sample times. AT III activity was not significantly different between the groups at any sample time. Within-group analysis showed significantly lower APTT ratio and heparin concentrations at 4 hours compared with the respective 2 hour values. These results would suggest that there is a potential impairment of anticoagulation with low-dose intravenous nitroglycerin and to a lesser extent with low-dose isosorbide dinitrate. Early and frequent monitoring may therefore be appropriate when intravenous nitrates and heparin are used in combination.     

The activated partial thromboplastin time of diluted plasma: variability due to the method of fibrin detection

The purpose of this study was to determine the effects of the dilution of plasma (1/3 in saline) on the kinetics of fibrin generation in the activated partial thromboplastin time (APTT) assay. The diluted APTT is considered to increase the sensitivity of the APTT test however, studies in our laboratory using an electro-optical fibrin detection system failed to show significant differences in APTT values obtained with diluted and undiluted canine plasma. Seventeen plasmas, including plasmas moderately and markedly deficient in intrinsic factor activity were assayed in the undiluted and diluted APTT assay using two methods for fibrin endpoint detection; a visual "tilt-tube" technique and an electro-optical detection system. In the former technique the endpoint was the formation of a visible fibrin web or clot; in the latter procedure the end point was the first detection of a change in optical density of the plasma. Optical density changes during fibrin formation were also recorded ( thrombokinetograms ). The results indicated that the electro-optical fibrin detection system failed to identify a prolongation of the APTT as a result of 1/3 plasma dilution; a prolongation that was consistently observed with the visual fibrin detection technique. Plasma dilution however, did significantly reduce the rate of fibrin production as indicated by the thrombokinetogram profile. It was concluded that the dilution of plasma with saline, as has been used to increase the sensitivity of the APTT assay procedure, has little effect on the time of onset of fibrin formation in a given plasma. The major effect appears to be on the way in which fibrin forms in that the polymerization/crosslinkage events associated with macroscopic fibrin production are delayed.     

液体活化部分凝血活酶试剂的制备及其质量评价

目的　制备液体活化部分凝血活酶试剂 ,并对其质量进行评价。方法　用兔脑为原料 ,改进常规方法制备液体活化部分凝血活酶试剂 ,并对其灵敏度、重复性、稳定性、瓶间差等评价。结果　该试剂的灵敏度、重复性、稳定性等均令人满意 ;与进口试剂相比较相关性好(r =0 .975 6,P <0 .0 0 0 1) ,呈直线正相关。临床应用显示血友病患者和抗凝治疗患者的APTT结果明显延长。正常参考值范围为 2 8～ 44s。结论　自制液体活化部分凝血活酶试剂的质量可靠 ,可以应用于临床     

米非司酮对血小板及血浆凝血酶原时间的影响

目的探讨米非司酮对血小板、血浆凝血酶原时间的影响。方法检测200例药物流产孕妇服用米非司酮前后血小板数量、平均体积、血浆凝血酶原时间及出血量。结果服药前后血小板数量、平均体积及血浆凝血酶原时间比较无显著差异(P>0.05);阴道流血量>2倍经血量20例,占10%;阴道流血量>1倍经血量15例,占7.5%;阴道流血量与经血量相似135例,占67.5%;阴道流血量少于经血量30例,占15%。结论米非司酮对血小板、血浆凝血酶原时间无影响,如阴道流血多需及时清宫。     

仪器法测定凝血酶原时间的标准化

目的 :比较手工法和仪器法测定的国际标准化比率 (INR) ,研究全自动凝血仪对INR值测定的影响。方法 :分别用手工法和仪器法测定 2 0例健康人和 60例口服抗凝剂达 6w以上换瓣患者的PT值 ,计算出各自的INR值 ,进行t检验 ;用一种已知国际敏感指数 (ISI)的凝血活酶对仪器的特异性ISI值进行标定后再计算INR值 ,进行t检验。结果 :仪器法测定的结果在标定前与手工法有显著性差异 (P <0 0 5) ,标定后两种结果无显著性差异 (P >0 0 5)。结论 :凝血仪对INR值有影响 ,对仪器的特异性ISI值进行标定后可以消除此影响     

A modified whole blood partial thromboplastin test for the assessment of heparinization

Current methods of assessment of heparinization are either inconvenient as bedside procedures or lack correlation with the Lee-White whole blood clotting time over the therapeutic range. A new thromboplastin time (CAT time) has been developed to overcome these disadvantages by offering uniform contact activation. The test makes use of a partial thromboplastin activated by celite-adsorbed “contact factor”, thus eliminating the activation phase of the activated partial thromboplastin time. Preliminary experiments suggest that this modification will be helpful in the study of “contact factor” deficiencies.