A standardized glucose-insulin-potassium infusion protocol in surgical patients: Use of real clinical data from a clinical data warehouse.

AIMS: We evaluated the clinical usefulness of a new unified glucose-insulin-potassium (GIK) regimen in a general surgical department. METHODS: Surgical patients treated under the previous diverse GIK regimens (September 2016 to August 2017) and the new unified GIK regimen (September 2017 to August 2018) were identified in records of the Clinical Data Warehouse of Seoul National University Bundang Hospital. Serial and area under the curve (AUC) glucose levels, and percentages of time within the target glucose levels were compared in propensity score matched patients in the diverse GIK regimen and in the unified GIK regimen (n = 227 in each group). RESULTS: The AUC of glucose at 6 h and 12 h was lower under the unified GIK regimen than the diverse GIK regimen. The percentage of target glucose levels was higher in the unified GIK regimen compared to the diverse GIK regimen (81.5% vs. 75.0%, P = 0.026), but the occurrence of hypoglycaemia did not differ significantly between groups. CONCLUSIONS: The unified GIK regimen was more effective than the diverse GIK regimen for glycaemic control and did not increase the number of patients developing hypoglycaemia. This validated written GIK regimen can be safely used in a general surgical department.

Evaluation of serum electrolytes measurement through the 6-year trueness verification program in China.

Objectives: The National Center for Clinical Laboratories (NCCL) in China initiated a serum electrolyte trueness verification (ETV) program in 2014 for measurement standardization. Methods: Every year, two levels of fresh frozen commutable serum samples determined by inductively coupled plasma mass spectrometry (ICP-MS) reference methods were transported to participating clinical laboratories for the measurement of sodium, potassium, calcium and magnesium. Both samples were measured 15 times in 3 days, and the mean values and coefficient variations (CVs) were calculated from the results. The tolerance limits of trueness (bias), precision (CV) and accuracy (TE) based on the biological variation database were used as the evaluation criteria. The overall trend of the ETV program over 6 years was surveyed by calculating the pass rates of the participating laboratories. The mean bias, inter-laboratory CV, and TE of all laboratory results were analysed. Furthermore, homogeneous and heterogeneous systems were compared, and the bias and CV results of mainstream analysis systems were analysed. Results: Pass rates of the three quality specifications increased, and the overall mean bias and inter-laboratory CVs decreased. The homogeneous system was superior to the heterogeneous system for calcium and magnesium measurements. For sodium, potassium, calcium and magnesium, the minimum bias corresponded to Hitachi, Siemens, Beckman AU and Roche, respectively. For inter-laboratory robust CVs, no obvious differences were observed between each peer group. Conclusions: The commutable ETV materials assigned via reference methods can evaluate the accuracy and reproducibility of an individual laboratory and the calibration traceability and uniformity between laboratories for measurements.

Comparison of Nutrient Reference Values for Food Labeling in Japan with CODEX Recommendations, Based on DRIs and Nutrient Intake in Japan.

To clarify the degree of consistency between the international recommendations and the national Japanese system, the nutrient reference values (NRVs) adopted by the CODEX were compared with current Japanese NRVs 2015, the dietary reference intakes for Japanese (DRIs-J) 2015, and actual nutrient intake levels by the Japanese population. The Japanese NRV for protein was high relative to CODEX NRV-R (i.e., NRV-Requirement). The Japanese NRVs for folate and calcium were low, and vitamin K was high, relative to each CODEX NRV-R. However, it was similar to the DRI-J values, and current intake levels for the Japanese population. For iron, calculation methods were different between the CODEX and Japan. Japanese iron NRV was calculated based on the RDA without menstruatating women, whereas CODEX NRV-R was calculated based on the INL98 of all adult men and women. Actual intake levels of iron for the Japanese population were similarly low. The Japanese NRV for sodium was high and potassium was low based on DRI-J values, relative to the CODEX NRV-NCD. For nutrients that show large discrepancies between the CODEX and Japanese NRVs, the values should be discussed further.

Commutability of external quality assessment materials for serum sodium and potassium measurements.

Background The commutability of electrolyte trueness verification materials (ETVs) and commercial general chemistry materials (GCs) was evaluated to investigate their suitability for use in an external quality assessment (EQA) program for serum sodium and potassium measurements. Methods Eighty fresh individual human samples (40 for sodium measurements and 40 for potassium measurements), six ETVs and three GCs were analyzed by five routine methods (validated methods) and by inductively coupled plasma mass spectrometry reference methods (comparative methods) for the determination of sodium and potassium. The commutability was analyzed according to Clinical and Laboratory Standards Institute (CLSI) EP14-A3 protocol and difference in bias approach, respectively. The linearity, bias and imprecision of the routine methods were also assessed according to CLSI guidelines. Results According to EP14-A3 protocol, ETVs were commutable for all assays, and GCs were commutable for 3/5 assays for sodium. ETVs were commutable in most assays except Cobas C501, while GCs showed no commutability except in case of AU5821 for potassium. According to a difference in bias approach, the commutability of ETVs was inconclusive for most routine assays for both sodium and potassium, and GCs were inconclusive for sodium and non-commutable for potassium in most routine assays. The routine methods exhibited excellent linearities and precisions. The majority and minority of relative biases between the routine and reference methods were beyond the bias limits for sodium and potassium, respectively. Conclusions Superiority in the commutability of ETVs over GCs was observed among the sodium and potassium assays whichever evaluation approach was applied.

An evidence- and risk-based approach to a harmonized laboratory alert list in Australia and New Zealand.

Individual laboratories are required to compose an alert list for identifying critical and significant risk results. The high-risk result working party of the Royal College of Pathologists of Australasia (RCPA) and the Australasian Association of Clinical Biochemists (AACB) has developed a risk-based approach for a harmonized alert list for laboratories throughout Australia and New Zealand. The six-step process for alert threshold identification and assessment involves reviewing the literature, rating the available evidence, performing a risk analysis, assessing method transferability, considering workload implications and seeking endorsement from stakeholders. To demonstrate this approach, a worked example for deciding the upper alert threshold for potassium is described. The findings of the worked example are for infants aged 0-6 months, a recommended upper potassium alert threshold of >7.0 mmol/L in serum and >6.5 mmol/L in plasma, and for individuals older than 6 months, a threshold of >6.2 mmol/L in both serum and plasma. Limitations in defining alert thresholds include the lack of well-designed studies that measure the relationship between high-risk results and patient outcomes or the benefits of treatment to prevent harm, and the existence of a wide range of clinical practice guidelines with conflicting decision points at which treatment is required. The risk-based approach described presents a transparent, evidence- and consensus-based methodology that can be used by any laboratory when designing an alert list for local use. The RCPA-AACB harmonized alert list serves as a starter set for further local adaptation or adoption after consultation with clinical users.

A candidate reference method for serum potassium measurement by inductively coupled plasma mass spectrometry.

BACKGROUND: Potassium is an important serum ion that is frequently assayed in clinical laboratories. Quality assurance requires reference methods; thus, the establishment of a candidate reference method for serum potassium measurements is important. METHODS: An inductively coupled plasma mass spectrometry (ICP-MS) method was developed. Serum samples were gravimetrically spiked with an aluminum internal standard, digested with 69% ultrapure nitric acid, and diluted to the required concentration. The 39K/27Al ratios were measured by ICP-MS in hydrogen mode. The method was calibrated using 5% nitric acid matrix calibrators, and the calibration function was established using the bracketing method. RESULTS: The correlation coefficients between the measured 39K/27Al ratios and the analyte concentration ratios were >0.9999. The coefficients of variation were 0.40%, 0.68%, and 0.22% for the three serum samples, and the analytical recovery was 99.8%. The accuracy of the measurement was also verified by measuring certified reference materials, SRM909b and SRM956b. Comparison with the ion selective electrode routine method and international inter-laboratory comparisons gave satisfied results. CONCLUSIONS: The new ICP-MS method is specific, precise, simple, and low-cost, and it may be used as a candidate reference method for standardizing serum potassium measurements.

Candidate reference measurement procedures for chloride, potassium, sodium, calcium, magnesium, and lithium by inductively coupled plasma (isotope dilution) sector field mass spectrometry (ICP-(ID) SFMS) in serum.

BACKGROUND: Standardization of the measurement of electrolyte concentrations in serum is of considerable interest for quality assurance in patient care. To promote the ongoing process of standardization we developed candidate reference measurement procedures of highest metrological order for Cl, K, Na, Ca, Mg, and Li using ICP-(ID) SFMS. METHODS: Serum samples were diluted with 4 mmol/L nitric acid and were spiked with the internal standard for quantification, separately for each analyte. The samples were introduced in the ICP-SFMS device by continuous infusion using a peristaltic pump. The measurement results were compared with reference measurement procedure values obtained by atom absorption spectroscopy, flame emission spectroscopy, and coulometry. The measurement accuracy and precision was calculated by analyzing certified reference materials and EQAS samples. RESULTS: The mean coefficient of variation (CV) of the ICP-MS procedures for the serum samples was 0.65% for Cl, 0.46% for K, 0.51% for Na, 0.77% for Ca, 0.78% for Mg, and 0.58% for Li. The mean bias from target values of NIST certified reference materials was +0.85% for Cl, -0.46% for K, +0.68% for Na, -0.21% for Ca, +0.27% for Mg, and -0.39% for Li. CONCLUSIONS: Candidate reference measurement procedures for 6 electrolytes were developed by high performance magnetic sector field ICP-MS fulfilling the requirements of ISO 15193:2009 for reference measurement procedures with traceability to SI according to ISO 17511:2003 and can be used for setting target values in EQAS and for certification of reference materials.

Standardising dialysate potassium does not increase patient risk.

BACKGROUND: Rapid intradialytic potassium shifts during haemodialysis have been associated with increased mortality and morbidity. Standardising dialysate potassium to 2 mmol/l may decrease the potassium shift. OBJECTIVE: To examine the effect of standardising dialysate potassium to 2 mmol/l for all chronic dialysis treatments. DESIGN: Pre- and post-intervention comparison of monthly serum potassium. PARTICIPANTS: Ninety-seven individuals, of whom 56 patients could be matched across both data collection periods. METHODS: Serum potassium data were categorised based on a target range 3.5-6.0 mmol/l. Overall pre- and post-intervention mean scores were compared using a paired samples t-test. Data for patients routinely prescribed dialysate potassium 1 mmol/l pre-intervention (n = 6) underwent paired samples t-test to compare their mean serum potassium pre- and post-intervention. RESULTS: There was no statistically significant change in serum potassium post-intervention. The majority of patients remained within the target range, including the subset of patients who had a history of high serum potassium during the pre-intervention period. CONCLUSIONS: A standard potassium dialysate of 2 mmol/l may reduce intradialytic serum potassium shifts and may assist in standardising safer work practices.

Practical solution for control of the pre-analytical phase in decentralized clinical laboratories for meeting the requirements of the medical laboratory accreditation standard DIN EN ISO 15189.

This report was written in response to the article by Wood published recently in this journal. It describes a practical solution to the problems of controlling the pre-analytical phase in the clinical diagnostic laboratory. As an indicator of quality in the pre-analytical phase of sample processing, a target analyte was chosen which is sensitive to delay in centrifugation and/or analysis. The results of analyses of the samples sent by satellite medical practitioners were compared with those from an on-site hospital laboratory with a controllable optimized pre-analytical phase. The aim of the comparison was: (a) to identify those medical practices whose mean/median sample values significantly deviate from those of the control situation in the hospital laboratory due to the possible problems in the pre-analytical phase; (b) to aid these laboratories in the process of rectifying these problems. A Microsoft Excel-based Pre-Analytical Survey tool (PAS tool) has been developed which addresses the above mentioned problems. It has been tested on serum potassium which is known to be sensitive to delay and/or irregularities in sample treatment. The PAS tool has been shown to be one possibility for improving the quality of the analyses by identifying the sources of problems within the pre-analytical phase, thus allowing them to be rectified. Additionally, the PAS tool has an educational value and can also be adopted for use in other decentralized laboratories.

Risk assessment of physico-chemical contaminants in groundwater of Pettavaithalai area, Tiruchirappalli, Tamilnadu - India.

A study was carried out in Pettavaithalai area to evaluate the current status of physico-chemical contaminants and their sources in groundwater. Groundwater samples collected from pettavaithalai area in 15 different stations were analyzed every alternative months over a period of two years from August 2000 to June 2002. A sugar mill is situated at the heart of the study area. Three profiles (profile A, B and C) were selected based on the direction in which the sugar mill effluent flows. In each profile five samples were collected from five different station at a regular distance of about 1 Km. The physico-chemical parameters such as pH, EC TDS, TH, NO3, SO4, PO4, Na, K, Ca, Mg, DO, BOD and COD have been analyzed. The results showed that among the three profiles, many of the estimated physico-chemical parameters of profile C were very high when compared to profile B and A which indicates the poor quality of the groundwater around this area.

Analysis of physical and chemical parameters of bottled drinking water.

Seventeen different brands of bottled drinking water, collected from different retail shops in Amritsar, were analyzed for different physical and chemical parameters to ascertain their compliability with the prescribed/recommended limits of the World Heath Organization (WHO) and the United States Environmental Protection Agency (USEPA). It was found that the majority of the brands tested were over-treated. Lower values of hardness, total dissolved solids (TDS) and conductance than the prescribed limits of WHO showed that water was deficient in essential minerals. Minerals like magnesium, potassium, calcium and fluoride were present in some cases in such a low concentration that water seemed to be as good as distilled water. Samples showing fluoride lesser than 0.5 mg/l warranted additional sources of fluoride for the people consuming only bottled water for drinking purposes. Zero values for chlorine demand as shown by all the bottled water samples showed that water samples were safe from micro-organisms. In case of heavy metals, only lead had been found to be greater than the limit of 0.015 mg/l as prescribed by WHO and USEPA, in seven out of 17 samples. Lead even at such a low concentration can pose a great health hazard.

A contactless conductivity detector for capillary electrophoresis: effects of the detection cell geometry on the detector performance.

The effect of the gap between the electrodes and of their width on the behavior of a capacitively wired contactless conductivity detector was studied. The results obtained have indicated that the detector response can be qualitatively described by a model based on the concept of the effective electrode width which is a complex parameter determined by the gap between the electrodes, the frequency of the input signal and the conductivity of the test solution. The detector sensitivity and the effect on the separation efficiency depend on the difference between the effective and geometric electrode widths. Higher detection sensitivities have been attained for detectors with wide electrodes operating at lower frequencies, however, better separation efficiencies have been achieved using detectors with narrow electrodes and higher operational frequencies. The noise increases with decreasing gap between the electrodes and increasing frequency, especially with detectors employing narrow electrodes.

Urinary excretion measurements for the assessment of body burden of radiocaesium in man: differences between potassium and creatinine normalisation.

Relationships between 24-h urinary excretion and body burden of 137Cs obtained in a south-Swedish population, together with data from the literature, were applied to urine samples collected in 1994-95 from adult subjects living in Russia, in order to estimate their average body burden of 137Cs. Estimates obtained through creatinine normalisation of the 137Cs content in the Russian urine were a factor of 2 higher than estimates obtained through potassium normalisation. The accuracy of both these normalisation methods is discussed, as well as the influence of the difference in dietary habits between the two populations.

Transferability of results obtained for sodium, potassium and chloride ions with different analysers.

In this study we have assessed transferability in seven different analysers commonly used in clinical chemistry laboratories to measure sodium, potassium and chloride ions. The inaccuracy and linearity of the techniques were satisfactory in most cases, and therefore all the equipment may be used in both pathological and normal ranges of the electrolytes evaluated. In most cases it was possible to correct the inaccuracy. The equipment which gave the best performance when analysing the three ions assessed after considering the Process Capability Index (CPI) and Performance Index (PI) was Nova-5. According to Hyltoft-Petersen's criteria, the results obtained for the three ions with the different analysers cannot be used indiscriminately, apart from potassium. However, after comparison of the results obtained by indirect potentiometry with those obtained by other techniques, we can conclude that the transferability of results is possible in almost every case, as standard deviation from regression (Sy,x) was lower than the permissible analytical error.

Intrinsic and routine quality of serum total potassium measurement as investigated by split-sample measurement with an ion chromatography candidate reference method.

We evaluated the intrinsic quality of eight routine test systems for the measurement of serum total potassium (K+), as well as the routine quality of four of these systems, using a group of 60 single-donation serum samples that had been certified with an ion chromatography reference method. The intrinsic quality of the tests was evaluated by analysis of the sera in the manufacturers' application laboratories under strict internal quality control. The routine quality was evaluated by analysis of the same sera in five (per system) routine laboratories under daily working conditions. The results of the study were interpreted in light of the most stringent specifications derived from the biological variation of K+, which require limits of 6.3% for total error and 1.6% for systematic error. The study revealed that the intrinsic quality of all systems was excellent. None of the test systems yielded a substantial number of results outside the 6.3% total error limit, and only one test system exceeded the 1.6% systematic error limit. The majority of the routine laboratories reproduced the manufacturers' intrinsic quality. In particular, most laboratories satisfied the 6.3% total error limit. However, several laboratories exceeded the 1.6% systematic error limit. Generally, there was a considerable difference in quality between the participating laboratories. This showed that the major problems for serum K+ analysis (for samples with no unusual matrices and with concentrations within the reference interval) are at the routine laboratory.

[Nutritive value of daily food rations prepared in different regions of the country. III. The levels of calcium, phosphorus, magnesium, iron and potassium]. / Wartosc odzywcza calodziennych racji pokarmowych odtwarzanych w kilku regionach kraju. Cz. III. Zawartosc wapnia, fosforu, magnezu, zelaza i potasu.

Studies on the content of macrominerals in daily diets reconstructed in 1988 on the basis of the analysis of family budgets in 1986 carried out by the Central Statistical Bureau were carried on. Two social groups i.e. manual and mental workers with medium income were considered. The diets were prepared for 5 regions (Warszawa, Lublin, Olsztyn, Poznan, Wroclaw). According to the studies the requirements for calcium and magnesium were met in about 70% and those for iron in about 84%. The content of potassium in the diets was in the range of recommended allowances while the phosphorus exceeded the allowances by about 20-30%. The comparison of the presently studied diets with the ones from 1973, 1980, 1981 showed a lower degree of realization of the recommended intake of calcium and magnesium in 1986. The content of studied minerals in the diets was usually similar in all five regions.

Reference values of magnesium and potassium in mononuclear cells and erythrocytes of children.

Reference values for magnesium and potassium contents of mononuclear cells and erythrocytes were estimated in cord blood and in children from infancy through adolescence. No differences were detected between results for boys and girls. The mononuclear magnesium content was independent of age and was within the adult range of values. No significant correlation was shown between magnesium in serum and in mononuclear cells. Mononuclear potassium also showed no age-related differences. The correlation between magnesium and potassium contents in mononuclear cells was significant: however, the correlation was lower when the magnesium and potassium contents were expressed in terms of protein potent: micromoles or millimoles per gram of protein, respectively. The concentration of magnesium in erythrocytes was significantly lower in cord blood and during the first month of life, compared with that at older ages, and showed no significant correlation with serum magnesium. The concentration of erythrocyte potassium was independent of age and showed a low but significant correlation with erythrocyte magnesium content.

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.

Quality control slide for potassium hydroxide and cellufluor fungal preparations.

An opaque, water-insoluble quality control material with a skinlike microscopic appearance was prepared by inoculating melted xanthine (0.4%) agar with filamentous fungi and dispensing drops onto glass slides. After solidification of the agar, the material was rapidly cleared by 10% KOH, revealing fungal elements stained by Cellufluor reagent.