Improved estimation of fructosamine, as a measure of glycated serum protein, with the Technicon RA-1000 analyzer

We present an improved fructosamine assay for use with the Technicon RA-1000 analyzer. Features of this assay include: specimen throughput of 100 per hour, within-batch CV of 1.5%, between-batch CV of 2.4%, standard curve linear up to 24.9 mmol of fructosamine per liter, and good correlation (r = 0.82) with hemoglobin A1.     

Three direct spectrophotometric methods for determination of total bilirubin in neonatal and adult serum, adapted to the Technicon RA-1000 analyzer

We adapted three bichromatic spectrophotometric methods for determining total bilirubin in serum, for use with the Technicon RA-1000 analyzer. The borate buffer (BOR) of Hertz et al. (Scand J Clin Invest 1974;33:215-30), the caffeine buffer (CAF) of Vink et al. (Clin Chem 1988;34:67-70), and the combined borate-caffeine buffer (B-C) of Franzini and Cattozzo (Clin Chem 1987;33:597-9) were compared. All methods required only 10 microL of serum, were precise (between-batch CVs less than 4.2%, analyte range 64-310 mumol/L), linear to 1000 mumol/L, and insensitive to interference from hemoglobin to 5 g/L. Lipemia, carotene, and methemalbumin interfered positively with each method but insignificantly unless in supranormal concentrations. Only the BOR method was sensitive to protein matrix effect. Neonates' results obtained with all three methods compared well with a Jendrassik-Gróf-based technique. However, samples from adults with cholestasis were overestimated, particularly by the CAF method, but the BOR and B-C methods would be suitable for "stat" bilirubin analysis in these samples.     

NuLYTELY (PEG 3350, sodium chloride, sodium bicarbonate and potassium chloride for oral solution).

NuLYTELY (PEG 3350, Sodium Chloride, Sodium Bicarbonate, and Potassium Chloride for Oral Solution), a product from Braintree Laboratories, Inc. is a modification of GoLYTELY (PEG 3350 and Electrolytes for Oral Solution) that has been found to have the same therapeutic advantages in terms of safety, efficacy, speed and patient acceptance. This product was developed to improve upon the taste of GoLYTELY. NuLYTELY represents an effective alternative for bowel cleansing prior to colonoscopy that may be more acceptable to some patients.     

Reliability of IL Monarch ion-selective electrode module for sodium, potassium, and chloride measurements

We evaluated the IL Monarch random-access centrifugal analyzer for measurement of Na+, K+, and Cl- by an indirect potentiometric method. For different concentrations of control material, the total precision (CV) ranged between 0.82% and 1.14% for the three electrolytes; linearity was acceptable within a range of 103 to 215 mmol/L for Na+, 1.6-15.25 mmol/L for K+, and 80-173 mmol/L for Cl-. Data correlated well with those by flame photometry for Na+ and K+ and with those by coulometry for Cl-, both for various biological materials--sera, urines, dialysis fluids--and commercial control materials from various producers. Stability of the potentiometric signal was acceptable: daily variations were 0.2 mV for Na+, 0.05 mV for K+, and 0.03 mV for Cl-. Accordingly, we conclude that the system supplies reproducible and accurate results while being easy to use and requiring little maintenance. The use of indirect potentiometry offers results consistent with those obtained with traditional methods, and easily interpretable by clinical staff. However, better information about the actual ion activity in the tested sample for certain pathologies such as hyperlipemia and dysproteinemia could be obtained by methods involving direct potentiometry.     

血浆蛋白水平对间接离子选择电极法检测钾钠氯离子的影响

目的探讨血浆蛋白水平变化导致间接和直接离子选择电极法(ISE)结果间存在的差异,揭示直接ISE与间接ISE测定血浆钾、钠、氯离子结果之间的差异与血浆蛋白水平之间的关系。方法选取低、中、高血浆蛋白的独立样本,研究直接与间接离子选择电极法对血浆钾、钠、氯检测结果差异以及与蛋白水平之间的线性关系。结果间接法与直接法检测钠离子结果差异有统计学意义(P<0.05),钠离子结果差异与总蛋白、清蛋白离子回归方程分别为Y=-0.129 4 X+9.604 1和Y=-0.195 X+7.807 8,相关系数r(r2)分别为0.76(0.57)和0.61(0.37),均P<0.001。结论采用间接ISE法检测血浆钠离子时,对血浆蛋白水平的变化具有影响,直接与间接ISE法检测血浆钠离子结果差异和总蛋白、白蛋白水平之间线性回归等式可以成立。在总蛋白和(或)清蛋白水平明显异常时,直接ISE法测定血浆钠离子结果应当作为临床正确的依据。     

A comparison of reference method values for sodium, potassium and chloride with method-dependent assigned values

The concentrations of sodium, potassium, and chloride in various control sera were determined by reference methods. The reference method values were compared with the corresponding method-dependent assigned values. Sodium: Measurements by flame photometry and ion selective electrodes differed on the whole by less than 1% from the reference method value; determinations by photometry differed, however, by -4.7%. Potassium: The mean bias was -1.2% with flame photometry and -0.4% with ion selective electrodes, whereas nephelometric procedures differed by -1.9 or -4.8%. Chloride: Satisfactory agreement was obtained with values given for ion selective electrodes (-0.3%), for some coulometric procedures (-0.7 and 0.4%), and photometric determinations using mercury rhodanide (-0.5 and +0.7%). Values for mercurimetric titration and for photometric determinations using mercury 2,4,6-tri-(2-pyridyl)-s-triazine differed by + 2.5 and + 1.8%. Proposals concerning the allowable deviation from reference method values are discussed.     

应用酶法和电极法测定血清钾钠氯的实验对比

为了解酶法分析Ｋ＾＋、Ｎａ＾＋、Ｃｌ＾－的特点，应用电极法进行了实验对比，结果二种方法线怀范围和平均回收率均符合要求，精密度实验批内和批间ＣＶ值均在允许范围，但电极法明显优于酶法，同二种方法测定Ｋ＾＋、Ｎａ＾＋、Ｃｌ＾－的相关系数分别为０．９７６７，０．９７８５和０．９５２５，且差异不显著（Ｐ〉０．０５），溶血样品对二种方法测Ｋ＾＋均有明显正干扰，高脂血样品对电极法无干扰，而对酶法测Ｎａ＾＋，ＣＩ