电极法及酶法测定血清和肝素抗凝血浆中钾的探讨

目的 比较用电极法及酶法测定血清和肝素抗凝血浆中钾的差别,探讨肝素抗凝血浆用于钾检验的可行性。方法 采用日立7170A全自动生化分析仪,Beckman CX3生化仪,MEDICA K/Na/Cl检测仪测定50例病人的血清和肝素抗凝血浆的钾。结果 用电极法测定血清和血浆中钾结果基本一致,而用酶法测定血浆中的钾结果存在差异(P<0.01),血清钾浓度(Y)与血浆钾浓度(X)的回归方程为Y=1.007X+0.23,r=0.998。结论 电极法测定钾血清和血浆结果基本一致,肝素抗凝血浆适用于电极法测定钾,而用酶法测定钾时血清和血浆中存在恒定浓度差(约0.24 mmol/L),应给予纠正。     

肝素抗凝血浆测定钾的偏差探讨

目的:探讨肝素抗凝血浆急诊时在Hx-7185电解质分析仪上测定血钾的偏差。方法:采用Hx-7185电解质分析仪测定30例患者血清和肝素抗凝血浆钾的浓度。结果:血清钾浓度(Y)与血浆钾浓度(X)的回归方程为:Y=1.02X 0.31,r=0.9986。结论:用Hx-7185电解质分析仪检测肝素抗凝血浆钾和血清钾存在恒定浓度差(约0.38),与徐克及邱志林报道有差异,这是不同仪器及试剂引起的,即基质效应,并不是血浆钾与血清钾固有的浓度差异。     

肝素抗凝血浆用于急诊生化检验的探讨

目的：探讨肝素抗凝血浆用于急诊生化检验的可行性，方法：采用M644电解质分析仪和VITROS DTSC60干式生化仪，测定40例病人的血清和肝素抗凝血浆9项急诊生化项目。结果：血清和血浆中氯，葡萄糖，尿素，肌酐，肌酸激酶，胆碱酯酶，淀粉酶结果基本一致，钠稍有差异（P＜0．05），而钾存在明显差异（P＜0．01），血清钾浓度（Y）与血浆钾浓度（X）的回归方程为Y＝1．008X＋0．22,r=0.998，结论：肝素抗凝血浆适合于检验上述9项生化急诊项目，可快速报告结果，但需注意钾离子在血浆和血清中存在恒定浓度差（约0．23mmol/L)，应于以纠正。     

肝素抗凝血浆用于急诊生化检验的探讨

目的探讨肝素抗凝血浆用于急诊生化检验的可行性.方法采用M644电解质分析仪和VITROS DTSC60干式生化仪,测定40例病人的血清和肝素抗凝血浆9项急诊生化项目.结果血清和血浆中氯、葡萄糖、尿素、肌酐、肌酸激酶、胆碱酯酶、淀粉酶结果基本一致,钠稍有差异(P<0.05),而钾存在明显差异(P<0.01),血清钾浓度(Y)与血浆钾浓度(X)的回归方程为Y=1.008X+0.22,r=0.998.结论肝素抗凝血浆适合于检验上述9项生化急诊项目,可快速报告结果,但需注意钾离子在血浆和血清中存在恒定浓度差(约0.23 mmol/L),应于以纠正.     

血清与肝素锂抗凝血浆急诊生化项目的结果比较

目的探讨肝素锂抗凝血浆用于急诊生化检验的可行性,弄清血清与血浆结果之间的差异。方法在相同条件下采用美国雅培公司生产的Aeroset全自动生化分析仪对血清与肝素锂抗凝血浆14项常规急诊项目的检测结果进行对比分析。结果血清与肝素锂抗凝血浆中谷草转氨酶、尿素、淀粉酶、葡萄糖、二氧化碳总量差异无统计学意义(P>0.05),胆碱酯酶、肌酸激酶、乳酸脱氢酶、钾、钠、氯、钙、肌酐、尿酸差异有统计学意义(P<0.01~0.05),血清钾(Y)和血浆钾(X)的回归方程为Y=0.972X 0.16,r=0.924。结论肝素锂抗凝血浆适合于检验结果无显著差异的急诊项目,钾可通过回归方程校正后报告结果,对于差异显著的项目不能用血浆代替血清,报告时应注明并建立本实验室的参考值范围。     

肝素钠抗凝血浆测定电解质浓度及正常参考值研究

目的比较用间接电极法测定血清和肝素钠抗凝血浆电解质浓度的差别,探讨肝素钠抗凝血浆电解质浓度的正常参考值。方法采用罗氏MUDULARISE900模块式电解质分析仪检测70例体检者血清和肝素钠抗凝血浆的电解质浓度。结果血清与肝素抗凝血浆的K+、Na+、Cl-的测定结果差异有统计学意义(P<0.01),平均差值分别为0.24、1.42、0.94mmol/L,相对偏差分别为5.60%、0.99%和0.89%。Na+和Cl-差别小,相对偏差小于1%,在临床上无实际意义;K+的差异已超过5%,且相对恒定。统计1739例健康体检者肝素钠抗凝血浆电解质浓度,以x±2s为正常参考质范围,则K+:3.27～4.67mmol/L,Na+:137.9～147.5mmol/L,Cl-:99.2～110.8mmol/L。结论肝素钠是一种较理想的电解质抗凝剂,适合于电解质的测定,但是肝素钠抗凝血浆K+明显低于血清,不能沿用血清的正常参考值,建议各实验室建立自已的正常参考范围。     

抗凝剂在心肌肌钙蛋白Ⅰ测定中的影响初探

目的为缩短心肌肌钙蛋白Ⅰ（cTnⅠ）的检测周转时间（TAT）,探讨能否用血浆代替血清测定血液中cTnⅠ的浓度,从而通过减少分离样品所需的时间而达到缩短TAT的目的。方法使用Dade Behring OPLUS免疫分析仪分别测定10例患者乙二胺四乙酸（EDTA）、肝素抗凝血浆和血清中cTnⅠ的浓度,用SPSS统计软件包对检验数据进行配对t检验和相关性检验分析。结果（1）与血清cTnⅠ测定值相比,EDTA抗凝血浆平均偏低2．31％,肝素抗凝血浆平均偏低17．2％;（2）两种抗凝血浆与血清测定结果相关性良好,相关系数（r）分别为0．993和0．996;（3）EDTA抗凝血浆与血清cTnⅠ测定结果差异无统计学意义（P〉0．05）,肝素抗凝血浆与血清cTnⅠ测定结果差异有统计学意义（P〈0．01）。结论与血清相比,EDTA抗凝血浆对cTnⅠ的测定影响较小,肝素抗凝血浆对cTnⅠ测定有较大影响。为缩短cTnⅠ测定的TAT,可考虑采用EDTA抗凝血浆代替血清,以快速检测临床患者的cTnⅠ浓度,及时为临床评价心肌缺血损伤的程度提供依据。     

肝素锂抗凝血对电解质测定的影响

目的通过对用肝素锂抗凝血浆与不加抗凝剂的血清电解质测定结果的比较,了解肝素锂对电解质测定的影响。方法同时抽取同一对象不同添加物的2份标本共40份进行比较。结果肝素锂抗凝血对血钾测定有显著影响,对血钠及血氯测定差异无统计学意义(P>0.05)。结论肝素锂对血钾测定有影响,建议电解质测定最好采用不抗凝标本。     

血清肝素抗凝血浆对化学法检测微量元素的影响

目的 探讨不同处理方式的血清及不同肝素浓度抗凝血浆对化学法检测微量元素的影响。方法 以临床工作中可能出现的5种肝素浓度抗凝血浆与快速处理的血清标本在相同条件下配对检测微量元素，并与常规处理的血清标本进行比较。结果 不同浓度肝素抗凝血浆与快速处理的血清比较，铜（Cu）、镁（Mg）、锌（Zn）、铁（Fe）和总钙（TCa）差异无统计学意义（P〉0．05），磷（P）差异有统计学意义（P〈0．01）；快速与常规2种方式处理的血清比较：Mg、Zn和Fe差异有统计学意义（P〈0．05，P〈0．01）；不同浓度肝素抗凝血浆与常规处理的血清比较除TCa外差异均有统计学意义（P〈0．05，P〈0．01）；不同浓度肝素抗凝血浆之间比较差异无统计学意义（P〉0．05）。结论 如无条件快速处理血清，化学法检测微量元素应尽量使用肝素化抗凝血浆；肝素抗凝血浆的应用要充分考虑到个别项目如P的局限性；肝素抗凝浓度应按照《全国临床检验操作规程》执行，各实验室还应建立肝素抗凝血标本微量元素化学法检测指标的参考范围。     

抗凝剂血浆和血清对血无机磷测定的相关性探讨

目的了解4种抗凝剂血浆和对应血清测定血无机磷的相关性。方法以血浆为候选法及对应血清为标准方法 ,采用全自动生化分析仪直接测定。结果 4种抗凝剂抗凝血浆及对应血清平行测定结果为:肝素、草酸钾、EDTA-K2抗凝血浆及对应血清均有较好的相关性(r=0.890、0.818、0.848);回归系数假设检验,肝素、草酸钾、EDTA-K2抗凝血浆和对应血清回归方程比较差异有统计学意义(P0.05),呈直线回归关系。枸橼酸钠抗凝血浆及对应血清呈中度相关(r=0.762);回归系数假设检验,血浆和血清回归方程比较差异有统计学意义(P0.05),呈直线回归关系。结论肝素、草酸钾、EDTA-K2抗凝血浆能快速、准确地提供检测结果 ,与参考方法结果有可比性,而枸橼酸钠抗凝血浆检测结果与参考方法结果的可比性不如前者。     

Errors due to heparin in the estimation of plasma sodium and potassium concentrations

The effect of adding sodium heparin (5000 U/ml and 1000 U/ml) to whole blood on the concentrations of plasma sodium and potassium was examined. When the analysis was done by flame photometry both preparations of heparin caused an increase in plasma sodium concentration. If the analysis was done by a direct ion selective electrode method the 5000 U/ml heparin caused a decrease and the 1000 U/ml caused an increase in plasma sodium concentration. Plasma potassium concentration decreased when 1000 U/ml heparin was added irrespective of the method of analysis. It is recommended that sodium heparin should not be used in samples taken for estimation of sodium and potassium.     

Benzalkonium interference with test methods for potassium and sodium

Six automated instruments that measure sodium and potassium were tested for interference from two compounds used in catheters. Tridodecylmethylammonium heparin did not interfere with any of the methods. However, benzalkonium heparin falsely increased sodium measurement with the Kodak Ektachem, and falsely increased potassium measurements with three instruments (Beckman Astra, Baxter Paramax, and the Instrumentation Laboratory Monarch) in which ion-selective electrodes measure potassium in diluted serum. Three instruments in which ion-selective electrodes measure serum directly--Du Pont Dimension, Abbott Spectrum, and Kodak Ektachem--experienced no interference with potassium measurements. Interference of benzalkonium with potassium measurements may result from its interaction with the electrode membranes, which is accentuated in diluted serum.     

住院患者临床检测低血钾而无低钾症状的原因分析

目的探讨住院患者实验室检测低血钾而无临床低钾症状的原因,为消除临床诊断和治疗误区提供新思路及实验依据。方法对2010年3月至2011年2月该院750例血钾小于3.0mmol/L的住院患者进行回顾性分析。根据患者当时是否有低钾症状分为两组,对6个临床相关因素进行分析比较;另就高温下（30℃）肝素钠抗凝血对检测结果的影响做实验分析。结果 750例患者中495例有临床低钾症状,其发生率为66.0%;255例无低钾症状,发生率为34.0%,两组患者在年龄、季节、病区、心电图检查及血钾水平比较差异均有统计学意义（P〈0.05）;高温下肝素钠抗凝血放置2h即对离子选择性电极间接法检测钾离子有负干扰,且超出允许总误差。结论住院患者实验室检测低血钾而无临床低钾症状发生的原因与多种因素有关,临床应加强对有重病、慢性病的老年患者血钾的监测,早期诊断和治疗,预防患者发生无症状低血钾,夏季住院患者使用离子选择性电极间接法检测肝素钠抗凝血浆钾离子标本应及时送检,并使标本始终处于22～25℃,以确保检验结果对临床诊断的有效性。     

生化检验分析中肝素钠抗凝血浆应用的可行性分析

目的对生化检验分析中肝素钠抗凝血浆应用的可行性进行研究分析。方法对肝素钠抗凝血浆以及血清的10项生化项目的测定结果作相关比较,并提出对应的处理方法,选择20例本院门诊的患者,按照常规的方法抽取静脉血液4mL,各取一半分别注入2支不同的试管。其中一支试管不做抗凝处理,放置于37℃并水浴30min,然后通过离心分离出血清;另一试管含肝素钠抗凝剂,在加血之后立刻进行离心分离出血浆。钾(K+)、钙(Ca2+)、钠(Na+)、氯(Cl-)、镁(Mg2+)、葡萄糖(Glu)、血尿素氮(BUN)、肌酐(Cr)、丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST),以上10个项目指标均使用日立7080型的全自动分析仪来进行测定,并对结果进行记录。结果血清和血浆中Cl-、Ca2+、Mg2+、BUN、Cr、ALT、AST的检验结果基本一致;钠和葡萄糖差异有统计学意义(P<0.05);与钾差异也有统计学意义(P<0.01),血清钾浓度(Y)与血浆钾浓度(X)的回归方程为Y=0.715 X+0.499,r=0.749。结果清晰地表明了血清跟血浆中的K+、Glu、Na+测定值差异具有统计学意义(P<0.05),而其它的项目指标之间的差异无统计学意义(P>0.05)。结论采用肝素钠抗凝血浆进行生化检验分析,只要纠正了钾的差异或者可以考虑建立一个血浆钾参考值的范围即可迅速,准确地报告出结果,为协助临床医生的及时合理用药提供了技术保障。     

Reliability of the Hitachi sodium and potassium electrodes assessed

We compared the Hitachi 705 E sodium/potassium electrode system with the Radiometer flame photometer for measuring concentrations of sodium and potassium ions in serum and plasma. Our data show that the Hitachi results are slightly but significantly (less than 0.001) lower than the flame photometer results: Na+ 1.33 mmol/L for serum and 2.24 mmol/L for plasma; K+ 0.062 mmol/L for serum and 0.082 mmol/L for plasma. The magnitude of the bias varied considerably from day to day, ranging from -0.10 to 2.33 mmol/L for Na+ in serum and from 0.00 to 0.11 mmol/L for serum K+; for plasma specimens the corresponding ranges were -0.03 to 5.97 mmol/L and 0.00 to 0.17 mmol/L. These variations probably reflected difficulties in reproducing the calibration from day to day, because the daily means for a serum pool varied in parallel. We occasionally encountered serious problems with reproducibility.     

Total body potassium, skeletal muscle potassium and magnesium in patients with Bartter's syndrome

In 20 patients with Bartter's syndrome, who had a serum potassium concentration of 2.75 +/- 0.29 mmol/l (mean +/- SD), the total body potassium (TBK) was measured and compared with a predicted value obtained from regression equations based on age, sex, body height and weight. A significant difference was found between the observed and predicted TBK (mean -320 +/- 306 mmol, p less than 0.01). A positive correlation existed between the serum potassium concentration and the ratio observed TBK/predicted TBK. However, the average fractional reduction in TBK (-11%) was less than the average fractional decrease in serum potassium concentration (-32%). Muscle biopsy specimens were obtained from four patients with Bartter's syndrome and 10 control subjects for analyses of potassium and magnesium. The serum concentrations of potassium and magnesium were decreased in these patients. The potassium content in muscle tissue was lower in two of four patients, but no difference in the amount of magnesium was observed.     

Determination of sodium and potassium with ion-selective electrodes

We compared different sample-handling techniques for measurement of Na+ and K+ with ion-selective electrodes (ISE). Imprecision was less for venous blood (with a minimum of heparin) than for plasma, serum, or capillary blood. The results for K+ were higher for serum than for whole blood, and higher for whole blood than for plasma. The latter difference was apparently due to release of K+ during the analysis. Values were more stable for whole blood stored at 20 degrees C than at 4 degrees C or 37 degrees C. The molality of Na+ in the plasma of mixed whole blood changed by -10.5 mmol/kg per unit change in blood pH. This could be explained by the different H+ buffering capacities of plasma and erythrocyte fluid, because when the pH is changed, the concentration of small anions in erythrocytes changes more than it does in plasma, with a consequent osmotic movement of water across the erythrocyte membrane. When we took into account the residual liquid-junction potential and the mass concentration of water in each of 65 patients' sera, the molality determined for Na+ was 1% lower and that of K+ 3% lower by ISE than by flame photometry--differences that may be related to ionic binding or to a lower molal activity coefficient in serum than in the calibrator.     

Alpha 1-antitrypsin: the effect of anticoagulants on the trypsin inhibitory capacity, concentration and phenotype

The effects of anticoagulants on the determination of both trypsin inhibitory capacity and the concentration of alpha 1-antitrypsin measured by radial immunodiffusion, and on the alpha 1-antitrypsin phenotype were investigated. These results were compared with those obtained for serum. The following anticoagulants were investigated: sodium citrate; sodium oxalate; buffered citrate; potassium oxalate/sodium fluoride; sodium heparin; and potassium EDTA. It was found that plasmas from all of the anticoagulants, except sodium heparin, resulted in apparently significant decreases of both trypsin inhibitory capacity and concentration of alpha 1-antitrypsin measured by radial immunodiffusion, relative to serum. These decreases were not simply due to dilution by anticoagulants. Using both acid starch gel electrophoresis followed by immunofixation and isoelectric focusing in agarose, no interference was found in the phenotype determination. It is concluded that serum should be used to measure the trypsin inhibitory capacity or the concentration of alpha 1-antitrypsin by radial immunodiffusion, although plasma is also suitable provided that sodium heparin is used as the anticoagulant. The alpha 1-antitrypsin phenotype can be determined with either serum or any of the plasma. None of the anticoagulants employed in this study was present in excess.     

Colorimetric determination of potassium in plasma and serum by reflectance photometry with a dry-chemistry reagent.

We evaluated a colorimetric assay of potassium in plasma and serum with the Boehringer Mannheim Reflotron reflectance photometric analyzer, which is designed for near-patient testing in hospitals and physicians' offices. This potassium method does not require calibration or instrument maintenance by the operator. Analysis of 30 microL of plasma or serum takes approximately 140 s. Within-day imprecision (CV) was 1.0-1.2%. Total CVs over a 1-month period were 1.0-1.4%. Patients' results from the Reflotron correlated well with those from the IL 643 flame photometer and the Beckman Synchron CX3 ion-selective electrode methods. The accuracy of Reflotron values was also verified with Standard Reference Material 956 from the National Institute of Standards and Technology.