用胆红素在二点法测定肌酐中的负干扰计算其肌酐的测定值

用碱性苦味酸测定肌酐的Jaffe’s反应，血液中有很多物质产生干扰，造成假性肌酐，使肌研测定值偏高。为了克服这一干扰，在自动生化分析仪测定肌酐时，均采用二点法。然而胆红素在碱性苦味酸溶液中，510nm处吸光度会迅速下降，使二点法破性苦味酸测定肌酐呈负反应干扰[1]，本文通过实测胆红素在碱性苦味酸溶液中下降的吸光度与胆红素浓度呈正比，即脸红素浓度越高，下降的吸光度越大，与肌酐浓度无关。标本在二点法碱性苦味酸测定肌爵时，同时冽得该标本的脸红素含量，查出对应干扰量，两者相加即为该标本的真实肌酥量。1试剂与仪器①胆红…     

维生素C对三种常用肌酐测定方法的干扰

目的 探讨维生素C(Vc)对肌氨酸氧化酶法、苦味酸法、肌酐亚胺水解酶法检测血清肌酐(Cr)结果的影响.方法 在新鲜无黄疸、无溶血、无脂血的混合血清中加入不同浓度的Vc,分别用三种方法在迈瑞BS-300生化分析仪上检测血清中的Cr含量.结果 Vc在肌氨酸氧化酶法检测血清Cr时干扰随Vc含量的增加呈明显负增加,在苦味酸法检测血清Cr时干扰随Vc含量的增加呈明显正增加,而在肌酐亚胺水解酶法检测血清Cr时的干扰随Vc含量的增加变化不大.结论 Vc对肌酐亚胺水解酶法检测血清Cr干扰较小,临床应推广用此方法检测血清Cr.     

苦味酸携带污染使免疫透射比浊法测定结果偏高

苦味酸法利用碱性条件下肌酐(Cr)和苦味酸反应生成红黄色化合物来检测Cr,是目前国内测定Cr常用的方法之一。该法操作简便、成本低廉,但特异性不高,试剂常常干扰其他检测指标。我们发现Cr测定后进行免疫比浊定量检测时常会出现结果异常增高、复查时又趋正常的现象,经反复     

关于血清肌酐酶法分析特异性的几点讨论

血肌酐(creatinine,Cr)常规检测方法主要有两大类:化学法和酶法。化学法主要有碱性苦味酸终点法和碱性苦味酸二点动力学法。终点法的内源性干扰物种类太多,有的干扰物与苦味酸反应比Cr反应快,称为快干扰物,如乙酸、     

高铁氰化钾清除胆红素对碱性苦味酸动力学测定肌酐的干扰

碱性苦味酸动力学测定肌酐时胆红素对其有严重干扰,机制是碱性苦味酸与肌酐显色反应时在520nm 处吸光度增加,而胆红素在氢氧化钠作用下转化为胆绿素,使520nm 处吸光度下降,从而掩盖了肌酐的显色反应,导致结果偏低.本文参照Knapp     

酚磺乙胺对不同方法肌酐检测的影响

目的研究酚磺乙胺对肌酐检测方法影响。方法参照CLSI推荐的干扰试验标准，检测酚磺乙胺对酶法和碱性苦味酸法肌酐检测影响。结果试验标本和对照标本酶法肌酐检测结果差异明显，而碱性苦味酸法检测时两标本之间结果差异元统计学意义。结论当酚磺乙胺浓度达到0．3g／L时，对酶法肌酐检测有阴性干扰，对碱性苦味酸法检测无干扰作用。     

苦味酸法测尿液肌酐的改进

尿中肌酐含量测定,目前多用Jaffe 氏反应。苦味酸和NaOH 的用量,可直接影响方法的灵敏度和可靠性.笔者根据文献报道,对Jaffe 反应测定尿液肌酐所需苦味酸、NaOH 最佳浓度进行了选择,并改用磺基水杨酸溶液作尿的稀释液,排除蛋白质等物对肌酐测定的干扰。方法及结果如下.     

酚磺乙胺对不同方法测定肌酐的干扰

目的探讨酚磺乙胺对苦味酸法和肌氨酸氧化酶法测定肌酐的干扰情况。方法参照临床化学检验的干扰评价(CLSI EP7-A2)规则,设计配对差异试验和剂量试验,判断酚磺乙胺对苦味酸法和肌氨酸氧化酶法测定肌酐是否有干扰及干扰效应与酚磺乙胺浓度的关系。结果酚磺乙胺对苦味酸法测定肌酐有正干扰,对肌氨酸氧化酶法测定肌酐有负干扰,其干扰效应与酚磺乙胺浓度的关系均为二次曲线关系,酚磺乙胺对苦味酸法和肌氨酸氧化酶法测定肌酐的最小干扰浓度分别为0.070 g/L和0.016 g/L。结论酚磺乙胺对苦味酸法和肌氨酸氧化酶法测定肌酐均有干扰,在临床上必须采取措施避免这种干扰的出现。     

自动生化分析仪比色杯中反应残留物对酶法测定肌酐的干扰

目的对引起肌酐(Cr)酶法测定结果假性增高的原因进行分析。方法在日立7060C生化仪上,分别使用新、旧的2套比色杯,并使用2种Cr酶法试剂测定Cr。结果日立7060C比色杯使用较长时间后,发现测定过总蛋白(TP,双缩脲法)的比色杯,经过仪器清洗后,若该比色杯紧接着用A品牌的Cr试剂进行测定,可引起测定结果的假性增高;改用B品牌的Cr试剂,则未见测定结果的假性增高。更换新的比色杯后,测定过TP的比色杯对这2种品牌的Cr试剂都不产生比色杯携带污染,测定结果都不假性增高。结论日立7060C比色杯使用较长时间后,有些项目的反应产物可一定程度的吸附在比色杯上,引起比色杯携带污染,从而对一些抗干扰能力较差的试剂和项目产生干扰。     

利用Rate-Blank消除胆红素对肌酐测定的负干扰因素

目的分析苦味酸法测定肌酐时胆红素干扰物质的影响,探讨一种消除胆红素干扰苦味酸法测定肌酐的方法。方法在日立7170A全自动生化分析仪上设定两种苦味酸测量肌酐的方法,一种为RateA,另一种利用带血清信息的空白速率(Rate-Blank)RateA法,参数设定为测定方法RateA,反应时间10分钟,读数点〔19 23 11 15〕。用两种方法分别测定正常体检组、高胆红素组标本血清肌酐的浓度。将以上两种方法测得的结果与酶法测得的结果进行对比分析。结果高胆红素对Rat-eA法测量肌酐有明显负干扰,采用Rate-Blank RateA法后此干扰明显降低。结论采用Rate-Blank RateA可基本消除胆红素对苦味酸测定肌酐的干扰。     

Improved liquid-chromatographic method for determination of serum cortisol.

We describe a specific and precise method for measuring concentrations of cortisol in serum or plasma by liquid chromatography. Cortisol, together with an internal standard, equilenin, is extracted from 1 mL of serum or plasma and analyzed isocratically on a reversed-phase column with a mobile phase of acetonitrile/phosphate buffer (30/70, by vol.), at a flow rate of 2.0 mL/min. The eluted cortisol is detected by its absorption at 254 nm and quantitated by peak height measurements. Each analysis requires no longer than 15 min at the optimum column temperature of 50 degrees C. The lower limit of detection for cortisol is about 2 ng/sample for a standard solution; sensitivity is routinely 5 micrograms/L of serum. Analytical recoveries exceeded 95%, with good day-to-day precision (coefficients of variation between 4 and 7%). Of more than 50 drugs and steroids tested for possible interference, only the steroids cortisone, prednisone, and prednisolone may interfere with the analysis of cortisol.     

Pretreatment of serum containing hemoglobin vesicles (oxygen carriers) to prevent their interference in laboratory tests.

Hemoglobin vesicles (HbV, diameter: 251 +/- 81 nm) are artificial oxygen (O2) carriers encapsulating concentrated hemoglobin (Hb) solution with phospholipid bilayer membrane, and their O2 transporting ability in vivo has been extensively studied. It is important to clarify the interference of the HbV suspension in clinical laboratory tests performed on serum and to establish a pretreatment method to avoid such an interference. The HbV suspension, acellular Hb solution ([Hb] = 10 g/dl) or saline, was mixed with a pooled human serum at various ratios up to 50 vol% ([Hb] = 5 g/dl), and the magnitude of the interference effect of HbV and Hb on 30 analytes was studied. The mixture of the HbV suspension and serum was ultracentrifuged (50,000 g, 20 min) to remove the HbV particles as precipitate, and the supernatant was analyzed and compared with the saline control group. The HbV particles were also removed by centrifugation (2,700 g, 30 min) in the presence of dextran (Mw 200 kDa). The HbV suspension showed considerable interference effects in most analytes. The majority of these effects was more serious than those of the acellular Hb solution. These findings are thought to be due to the light absorption of Hb in HbV and/or the light scattering generated in the suspension that interferes with the colorimetric and turbidimetric measurements. The components of HbV may also interfere with the chemical reactions of the studied assays. However, removal of the HbV from the supernatant diminished the interference in most of the assays: this is an advantage of HbV in comparison with acellular chemically modified Hb solutions.     

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.     

血清类风湿因子对免疫比浊法测定甘胆酸的影响评估

目的评估类风湿因子对血清甘胆酸测定的影响并探讨结果审核办法。方法用含有高水平类风湿因子的血清分别稀释不同水平的甘胆酸血清样本,测定原始和不同稀释度的血清样本类风湿因子和甘胆酸水平,观察稀释后测定结果的变化曲线,确认干扰存在;同时平行检测抗核抗体,观察干扰情况。结果添加类风湿因子后的血清甘胆酸测定结果下降,与类风湿因子水平呈正相关,差异有统计学意义(P<0.05)。类风湿因子水平在545 IU/mL以下时对血清甘胆酸测定基本没有影响,随着水平升高,干扰强度上升,甘胆酸检测结果急剧下降;未观察到抗核抗体干扰甘胆酸的测定。结论血清样本中较高水平的类风湿因子会干扰甘胆酸的测定,导致血清甘胆酸水平假性降低,需要引起临床重视。结果审核时应结合血清丙氨酸氨基转移酶、天门冬氨酸氨基转移酶、总胆汁酸综合分析报告血清甘胆酸结果。     

高效液相色谱法对溶液中氯己定含量的测定

用高效液相色谱法 ,于氯己定有特征吸收峰且干扰较小的 2 53nm波长下测定溶液中氯己定含量。对氯己定含量≤ 0 4 2 2 2mg/ml的溶液 ,测定结果的相对偏差≤ 1 4 %。     

Thin layer broadband porous chromium black absorber fabricated through wet-etching process

A thin layer porous chromium (Cr) black absorber was fabricated on a polyimide (PI) substrate with 2 inch diameter and 500 nm thickness. The chromium black was prepared by electron beam evaporation and wet-etching process. To optimize the parameters of the absorber, the Cr black was firstly fabricated on silicon and quartz wafers. A high average absorption of 93% over the whole visible spectrum (320 nm to 800 nm) was obtained by 3 min wet-etching of a 400 nm thick metal Cr film. The absorption was higher than 65% when the spectrum extended to near infrared from 800 to 1800 nm. The mechanism of the ultra-broadband absorption can be explained by the light trapping by numerous nanovoids formed inside the Cr film. The nanovoid acts as a blackbody cavity, where the incident light experienced multiple reflections. Using the optimized parameters obtained with silicon and quartz wafers, the Cr black absorber was fabricated on a PI film. Due to its porous structure (low density) and thin thickness, the Cr black/PI composite film showed a strong light absorption and a high optical thermal response. Compared to a PI film without Cr black layer, the average absorption of the composite film was increased from 5.0% to 93.4%, the optical thermal response was improved by 43.5 times. This property highlights its potential applications in various fields such as photo detection and thermal imaging.

Thin layer broadband porous Cr absorber with 93% absorption in whole visible range was fabricated on a free-standing polyimide film by wet-etching.     

血清甲状腺球蛋白及其自身抗体在化学发光免疫分析时的相互影响

目的探讨血清甲状腺球蛋白(Tg)及其自身抗体(TgAb)在化学发光免疫分析时的相互影响。方法在高浓度Tg血清中加入不同浓度TgAb血清,测定Tg回收率;在高浓度TgAb血清中加入不同浓度Tg血清,测定TgAb回收率。结果加入低、高浓度TgAb血清后,Tg回收率分别为93%~112%和17%~40%,Tg回收率和TgAb浓度呈负相关(rs=-0.877,P=0.001);加入低、高浓度Tg血清后,TgAb回收率分别为76%~108%和66%~98%,TgAb回收率和Tg浓度呈负相关(rs=-0.881,P=0.004)。结论血清Tg和TgAb在化学发光免疫分析时存在相互影响,导致结果偏低并呈浓度依赖性,其中TgAb在低浓度时即对Tg产生显著干扰,而Tg在较高浓度时才对TgAb测定产生明显影响。     

维生素C对3种血糖检测方法的干扰效应分析

目的探讨维生素C对3种不同方法检测血糖所造成的干扰效应。方法参照CLSI EP7-A2文件,将系列浓度的维生素C溶液按照5%体积加入到新鲜混合血清中,分别用己糖激酶法(方法 A)、葡萄糖氧化酶法(方法B)、葡萄糖还原酶电极法(方法 C)检测混合血清的葡萄糖水平,评价维生素C对3种不同方法检测血糖的干扰程度。结果维生素C在1 250mg/L时对方法 A测定血糖无干扰。在156mg/L时对方法 B产生临床不可接受的负干扰,对方法 C产生临床不可接受的正干扰,并且对2种方法的干扰程度随着维生素C的浓度升高而升高。相同浓度的维生素C对同一方法测定不同水平血糖的影响无明显差异。结论高浓度维生素C对葡萄糖氧化酶法和葡萄糖还原酶电极法测定血糖均会产生明显干扰。     

超声波对高分子材料降解过程启动的控制

背景：可降解高分子材料在植入体内后其降解过程就开始启动,如何能控制可降解材料降解过程的启动,做到定时、定位启动,国内外鲜有研究。 目的：研究超声波对高分子材料降解过程启动的控制。 方法：将ε-己内酯／L-丙交酯共聚物制成样本的可降解内核,在其表面通过4种方法涂覆低密度聚乙烯疏水涂层：①先将内核表面黏附一薄层CaCl2粉末,而后将聚乙烯涂覆于其表面。②先将聚乙烯涂覆于内核表面,静置粗化3h。③将内核表面黏附一薄层CaCl2粉末,而后将聚乙烯涂覆于其表面,静置粗化3h。④直接将聚乙烯涂覆于内核表面。将4种样本包埋于带皮猪肉内进行体外超声波轰击实验。 结果与结论：方法1、4制备的样本,在轰击前其疏水层能够保护内核材料,其浸泡液在631nm处无吸收峰值;轰击后由于疏水层破损,甲苯胺蓝染料被释放出来,造成溶液颜色改变及631nm处吸收峰值明显升高。方法2、3制备的样本,在轰击前其疏水层未能起到保护作用,其浸泡液在631nm处出现吸收峰值。电镜扫描显示4组样本在超声波作用下发生了明显表面容貌变化。表明采用低密度聚乙烯制作的疏水层可以保护内核ε-己内酯儿-丙交酯共聚物材料,以体外超声波作为诱发因素,可以控制可降解内核降解过程的启动。     

Towards better meta-analyses in assisted reproductive technology: Fixed,random or multivariate models?

AIM: To study the validity of the fixed, random, and multivariate meta-analytical models applied in meta-analyses in artificial reproduction technique. METHODS: Based on common characteristics of in vitro fertilization(IVF) meta-analyses, we simulated a large number of data to compare results issued from the fixed model(FM) with the random model(RM). For multiple endpoints meta-analysis(MA), we compared the univariate RM with the multivariate model(MM). Finally, we illustrate our findings in re-analyzing a recent MA. RESULTS: In our review, although a homogeneous effect was excluded in 89% of the MAs(11%), FM was utilized in 41 studies(82%). From simulations, a concordance of 59% ± 6% was found between the two tests, with up to 65% of falsely significant results with FM. The Q-test on studies characterized by substantial heterogeneity falsely accepted homogeneity in 46% of studies. Comparing separate univariate RM and MM on multiple endpoints studies, MM reduces the between endpoint discrepancy(BED) of 68%, and increases the power of 57% ± 8%. In the example dealing with the controversial effect of luteneizing hormone supplementation to follicle stimulating hormone during ovarian stimulation in IVF cycles, MM reduced BED by 66%, and consistent effects were found for all the endpoints, irrespective of partial reporting. CONCLUSION: The FM generally may produce falsely significant differences. The RM should always be used. For multiple endpoints, the MM constitutes the best option.