Influence of pre-analytical and analytical factors on osteoprotegerin measurements

IntroductionOsteoprotegerin (OPG), an osteoclastogenesis inhibitor implicated in bone remodelling, has emerged as a potential biomarker for cardiovascular disease. In order to implement OPG determination in the clinical laboratory, it is crucial to identify the most appropriate specimen type, preparation and measurement conditions. The present study focuses on identifying the pre-analytical variables that may influence OPG measurements.MethodsSerum and plasma (in EDTA, heparin and citrate) were collected from 45 healthy volunteers (men (n = 21, 46.7%), women (n = 24, 53.3%)). OPG was analysed by ELISA. The influence of the centrifugation speed, the number of freeze–thaw cycles, delay in sample processing, thermo-stability and endogenous interfering agents (haemolysis, triglycerides, bilirubin, cholesterol and RANKL) were studied.ResultsOPG concentrations were significantly lower (p < 0.0001) in serum (1015 ± 357 pg/mL) than in all plasma samples (1314 ± 448 pg/mL in EDTA, 1209 ± 417 pg/mL in heparin and 1260 ± 498 pg/mL in citrate).Increasing centrifugation speed (200 g to 3000 g) did not change serum OPG concentration (p = 0.88). However, OPG concentration significantly increased when centrifuged serum samples were stored at 48 h at room temperature (p < 0.0001). Repeated freeze–thaw cycles did not modify OPG levels until 4 cycles (p < 0.0001). Increasing time before processing the samples (2 h and 6 h) raised OPG concentrations both at room temperature (p < 0.0001) or 4 °C (p < 0.001).Positive concentration-dependent interference of triglycerides was found in the analysed pooled samples; however, OPG concentrations were falsely diminished with haemoglobin interference. Bilirubin, cholesterol and RANKL did not interfere with OPG measurements.     

Influence of pre-analytical and analytical factors on soluble CD40L measurements

The soluble form of CD40L (CD40 ligand), a pro-atherogenic mediator, has emerged as a diagnostic and prognostic marker for cardiovascular events. However, as platelets can shed CD40L upon activation, accurate measurement has proved challenging. The present study addresses the controversy regarding the appropriate specimen and preparation for laboratory evaluation of blood sCD40L (soluble CD40L). Serum and plasma (collected in EDTA, citrate or heparin) were collected from healthy volunteers (n=20), and sCD40L was analysed by ELISA immediately or after one to three freeze-thaw cycles and at different centrifugation speeds. Urine sCD40L levels were measured in subjects with low- and high-plasma sCD40L levels. Serum sCD40L levels (5.45+/-4.55 ng/ml; P<0.001) were higher than in citrate, EDTA or heparin plasma (1.03+/-1.07, 1.43+/-1.03 or 1.80+/-1.25 ng/ml respectively), with no significant differences between plasma preparations. Increasing g values (200-13000 g), which gradually deplete plasma of platelets, yielded lower sCD40L levels. Repeated freeze-thaw cycles significantly (P<0.05) increased sCD40L concentrations in platelet-rich, but not platelet-depleted, plasma (up to 2.4-fold). Bilirubin and haemoglobin interfered positively, and triacylglycerols (triglycerides) and cholesterol quenched CD40L signalling. No sCD40L was detected in urine samples. In conclusion, serum yields higher sCD40L concentrations than plasma; accurate measurements of sCD40L require exclusion of platelets and avoiding their post-hoc activation. Samples with high concentrations of bilirubin, haemoglobin and/or triacylglycerols should be excluded, as these substances interfere with the assay.     

粪便钙卫蛋白不同检测方法分析前及分析中影响因素分析

目的探讨粪便钙卫蛋白(fecal calprotectin, FC)分析前及分析中影响检测结果的若干因素。方法选取炎症性肠病(inflammatory bowel disease, IBD)患者、其他肠道炎症疾病患者和体检健康者各30例作为研究对象,收集粪便样本,同时采用ELISA、荧光免疫层析法、胶体金法进行FC检测,观察分析前粪便样本贮存的时间、温度及留样时间和分析中检测方法学差异对FC测定结果的影响。结果 FC可以在25℃下稳定7 d,4℃保存下至少稳定14 d,25℃下FC平均降解率为42.1%。同一患者日间FC检测结果差异较大,变异系数(CV)为5.1%～80.2%,平均CV值为39.6%,清晨样本FC浓度最高,中午样本FC浓度最低。不同检测方法对于FC检测定性结果具有较好的一致性,但对于定量结果的一致性差,量值结果不具备可比性。结论为提高FC检测的准确性,推荐将清晨第一次排便的标本作为检测样本,标本在离体后应在低温环境下尽快送检。对于IBD患者病情监测与疗效评估,FC检测结果需考虑方法学差异。     

Global maternal mortality: contributing factors and strategies for change

As the 2004 Fulbright Scholar to the Russian Federation, Dr. Callister was asked to give this address at the Meetings of the International Commission on the Status of Women, United Nations, March 8, 2004, New York City. MCN is proud to be able to share this with its readers.     

Variations in plasma protein concentrations in individuals with ulcerative colitis: analytical and biological factors

Eight plasma proteins were determined in specimens taken every second day during a 14 day period from eleven patients with acute ulcerative colitis. The intra-individual variations in the concentrations of albumin, orosomucoid, haptoglobin, IgG, IgA, IgM and complement factors C3 and C4 were larger than expected in normal persons. A two-way analysis of variance was applied to the normalized protein values to estimate to what extent the observed variations could be explained by analytical errors and the influence of biological factors general to all proteins, such as changes in plasma volume and distribution between plasma and extravascular space. In half the non-operated patients the changes in all proteins could be explained by the above mentioned variations. The individual variations seen in the concentrations of haptoglobin, C4 and IgM occurred at random compared to the clinical state of the disease. Only the operated patients showed a more systematic sequence of protein changes.     

Metabolic syndrome: contributing factors and treatment strategies.

Metabolic syndrome is associated with increased risk for cardiovascular and cerebrovascular disease. The World Health Organization and National Cholesterol Education Program Adult Treatment Panel III have identified physiologic abnormalities associated with metabolic syndrome, including impaired glucose metabolism, high blood pressure, elevated cholesterol levels, and abdominal obesity. It is estimated that 47 million Americans have metabolic syndrome. A variety of therapies may help reduce the incidence and risk, including diet, weight loss, physical exercise, glycemic control, and pharmacological treatments. Nursing care is focused on developing an individualized plan of care that includes family members and providing education, psychosocial support, close monitoring, and continued follow-up to ensure adherence and success in achieving patient outcomes.     

Decision-making in clinical nursing: investigating contributing factors

BACKGROUND: This article describes the results of a study which investigated the contextual factors influencing clinical decision-making. Education and experience have been suggested by some as having a positive effect on clinical decision-making, and have been listed as being of high importance. Values, knowledge, clinical setting and stress have also been identified as being important to decision-making, with various rankings given by different researchers. AIM: The study was undertaken to determine relationships between occupational orientation (value to role), educational level, experience, area of practice, level of appointment, age and clinical decision-making in Australian nurses. The predictive ability of each factor on clinical decision-making was determined. METHOD: This correlational study examined Australian nurses' decision-making about some common nursing interventions and 'occupational orientation', educational level, experience, level of appointment, area of clinical speciality and age. A model was constructed using stepwise selection regression to predict the 'weight' of each variable in clinical decision-making. RESULTS: Education and experience were not significantly related to decision-making. The factor that accounted for the greatest variability to clinical decision-making was holding a professional occupational orientation, followed by level of appointment, area of clinical speciality, and age in that order. CONCLUSION: In contrast to other studies, experience and educational level were not found to influence decision-making strongly, the value of role was the most significant predictor. The model developed, however, only accounted for a low amount of variability in decision-making. The findings indicate that there are other factors affecting clinical decision-making that still require identification.     

Emerging infectious diseases: vulnerabilities,contributing factors and approaches

We live in an ever more connected global village linked through international travel, politics, economics, culture and human–human and human–animal interactions. The realization that the concept of globalization includes global exposure to disease-causing agents that were formerly confined to small, remote areas and that infectious disease outbreaks can have political, economic and social roots and effects is becoming more apparent. Novel infectious disease microbes continue to be discovered because they are new or newly recognized, have expanded their geographic range, have been shown to cause a new disease spectrum, have jumped the species barrier from animals to humans, have become resistant to antimicrobial agents, have increased in incidence or have become more virulent. These emerging infectious disease microbes may have the potential for use as agents of bioterrorism. Factors involved in the emergence of infectious diseases are complex and interrelated and involve all classifications of organisms transmitted in a variety of ways. In 2003, outbreaks of interest included severe acute respiratory syndrome, monkeypox and avian influenza. Information from the human genome project applied to microbial organisms and their hosts will provide new opportunities for detection, diagnosis, treatment, prevention, control and prognosis. New technology related not only to genetics but also to satellite and monitoring systems will play a role in weather, climate and the approach to environmental manipulations that influence factors contributing to infectious disease emergence and control. Approaches to combating emerging infectious diseases include many disciplines, such as animal studies, epidemiology, immunology, ecology, environmental studies, microbiology, pharmacology, other sciences, health, medicine, public health, nursing, cultural, political and social studies, all of which must work together. Appropriate financial support of the public health infrastructure including surveillance, prevention, communication, adherence techniques and the like will be needed to support efforts to address emerging infectious disease threats.     

Emerging infectious diseases: vulnerabilities, contributing factors and approaches

We live in an ever more connected global village linked through international travel, politics, economics, culture and human-human and human-animal interactions. The realization that the concept of globalization includes global exposure to disease-causing agents that were formerly confined to small, remote areas and that infectious disease outbreaks can have political, economic and social roots and effects is becoming more apparent. Novel infectious disease microbes continue to be discovered because they are new or newly recognized, have expanded their geographic range, have been shown to cause a new disease spectrum, have jumped the species barrier from animals to humans, have become resistant to antimicrobial agents, have increased in incidence or have become more virulent. These emerging infectious disease microbes may have the potential for use as agents of bioterrorism. Factors involved in the emergence of infectious diseases are complex and interrelated and involve all classifications of organisms transmitted in a variety of ways. In 2003, outbreaks of interest included severe acute respiratory syndrome, monkeypox and avian influenza. Information from the human genome project applied to microbial organisms and their hosts will provide new opportunities for detection, diagnosis, treatment, prevention, control and prognosis. New technology related not only to genetics but also to satellite and monitoring systems will play a role in weather, climate and the approach to environmental manipulations that influence factors contributing to infectious disease emergence and control. Approaches to combating emerging infectious diseases include many disciplines, such as animal studies, epidemiology, immunology, ecology, environmental studies, microbiology, pharmacology, other sciences, health, medicine, public health, nursing, cultural, political and social studies, all of which must work together. Appropriate financial support of the public health infrastructure including surveillance, prevention, communication, adherence techniques and the like will be needed to support efforts to address emerging infectious disease threats.     

粪便性状及分析前标本处理方式对钙卫蛋白检测结果影响探讨

目的 探讨采样方式、离心条件等相关分析前因素对不同性状粪便的钙卫蛋白(fecal calprotectin,FC)检测结果的影响,从而进一步优化粪便FC检测流程.方法 收集在上海交通大学医学院附属新华医院进行粪便FC项目检测的粪便标本357例,按照布里斯托大便分类量表进行性状评估.选取不同性状的粪便标本同时进行称量法和...     

Searching for the final answer: factors contributing to medication administration errors

Medication errors have reached epidemic proportions in the United States with proposed resolutions having little effect. Many errors go unreported because of nurses' fear of retaliation. Yet these unreported errors may contain the very information needed to uncover system flaws. Until all causes are examined and researched thoroughly, systems will continue to fail. These unknown factors contributing to medication errors will remain elusive unless health care providers are willing and able to focus attention where it is needed-on systems rather than individuals. Patients have enough fears when entering health care institutions; medication errors should not be one of them.     

A multicenter evaluation of the PCA3 molecular urine test: pre-analytical effects, analytical performance, and diagnostic accuracy

BACKGROUND: Measurement of prostate cancer gene 3 (PCA3) mRNA normalized to prostate-specific antigen (PSA) mRNA in urine has been proposed as a marker for prostate cancer. METHODS: We investigated pre-analytical effects, analytical performance, and diagnostic accuracy of a quantitative assay for PCA3. RESULTS: Urine specimens collected without prostate manipulation demonstrated low informative rates. However, specimens collected following digital rectal examinations of 3 or 8 strokes per prostate lobe demonstrated informative rates >94%. Across all urine specimen types, median PCA3 results did not show statistically significant differences (P>0.8). Measurements of controls of known mRNA content demonstrated percent recoveries of 100+/-15% for both PCA3 and PSA mRNAs. PCA3 mRNA total, intra-assay, inter-assay, and inter-site CVs were < or =17.1%, < or =14.0%, < or =9.9%, and < or =3.2%, respectively. Corresponding CVs for PSA mRNA assay were < or =11.5%, < or =8.6%, < or =7.9%, and < or =8.3%. Blinded assay of urines from 72 men with known prostate biopsy outcomes yielded areas under the curve from receiver-operating characteristic analysis of 0.7 at both research sites. Deming regression of individual PCA3 results between sites yielded slope=0.94, intercept=0.48, R=0.9677 (P<0.0001). CONCLUSIONS: The PCA3 assay is insensitive to pre-analytical factors, performs well analytically and correctly classifies a high percent of subjects with known prostate cancer status across research sites.     

Missed nursing care in Australia: Exploring the contributing factors

BackgroundNurses are increasingly ending their shifts with outstanding tasks and missing vital aspects of patient care. Research has indicated that this could have a detrimental effect on both nurse and patient outcomes. The connection between inadequate staffing levels and missed nursing care is well documented in the research. However, other contributing factors leading to missed nursing care remain uncertain. This scoping review seeks to identify the contributing factors to missed nursing care in an Australian context.AimTo determine the contributing factors to missed nursing care by registered nurses in Australian hospitals.MethodsMEDLINE, CINAHL, and PubMed were searched for primary and secondary research articles. A scoping review was conducted using the Joanna Briggs Institute methodology for scoping reviews. Data from the studies was analysed by two independent reviewers and presented with a narrative synthesis of the findings.FindingsSeventeen studies were conducted in Australia. The main contributing factors to missed nursing care were: Inadequate staffing, environmental factors, and urgent situations. Nurses’ poor insight into personal and professional accountability was also found to contribute to missed nursing care.DiscussionThis review adds an important perspective to the impact of staffing on missed nursing care due to the mandated nurse-to-patient ratios in Australia, which has not been investigated in other countries. It found that mandated nurse-to-patient ratios can lead to a reduction in missed nursing care.ConclusionFurther research is required into mandated nurse-to-patient ratios and a nurse's personal and professional accountability and missed nursing care.     

Elevated plasma homocysteine concentrations in severe preeclampsia and eclampsia

Homocysteine is an essential amino acid required for the growth of cells and tissues in the human body. Maternal hyperhomocysteinemia is associated with a number of placenta-mediated diseases such as preeclampsia. The aim of this study was to evaluate the plasma level of homocysteine and its association with severity of preeclampsia. A case-control study was performed with 32 mild preeclamptic patients, 25 severe preeclamptic patients, 16 eclamptic patients and 34 controls. Maternal plasma homocysteine concentration was measured prospectively at antenatal period by high-performance liquid chromatography. There were no significant differences in demographic characteristics between the study and control groups. Mean plasma levels of homocysteine in women with severe preeclampsia (16.7 +/- 10.1 micromol/l, mean +/- S.D., n = 25) and eclampsia (16.5 +/- 9.6 micromol/l, mean +/- S.D., n = 16) were significantly higher than those in mild preeclampsia (7.7 +/- 2.4 micromol/l, mean +/- S.D., n = 32) and controls (6.7 +/- 1.6 micromol/l, mean +/- S.D., n = 34) (p < 0.0001). It should be noted that plasma levels of homocysteine are not significantly different between mild preeclampsia and controls. In conclusion, plasma homocysteine concentrations are increased in severe preeclampsia and eclampsia, but not in mild preeclampsia.     

Frequency of pediatric medication administration errors and contributing factors

This study examined the frequency of pediatric medication administration errors and contributing factors. This research used the undisguised observation method and Critical Incident Technique. Errors and contributing factors were classified through the Organizational Accident Model. Errors were made in 36.5% of the 2344 doses that were observed. The most frequent errors were those associated with administration at the wrong time. According to the results of this study, errors arise from problems within the system.     

Going blank: factors contributing to interruptions to nurses' work and related outcomes

hall l.m., ferguson-paré m., peter e., white d., besner j., chisholm a., ferris e., fryers m., macleod m., mildon b., pedersen c. & hemingway a. (2010) Journal of Nursing Management 18, 1040–1047
Going blank: factors contributing to interruptions to nurses’ work and related outcomes Aim To examine interruptions to nurses’ work, the systems issues related to these and the associated outcomes. Background While some research has described the role interruptions play in medication errors, work is needed to examine specific factors in the nursing work environment that cause interruptions and to assess the impact of these on nurses’ work and patient outcomes. Methods The present study utilized a mixed method design that involved work observation to detect nursing interruptions in the workplace followed by focus groups with a subsample of nurses. Results A total of 13 025 interruptions were observed. Equal numbers of these took place on medical and surgical units. The predominant source of interruptions was members of the health team, who interrupted more frequently on medical units. Conclusions Differences in the type of patient and the care needs between medical and surgical units may be a contributing factor to these findings. As members of the health team were among the leading source of interruptions, an interdisciplinary team-based approach to changing the organization and design of work should be explored. Implications for nursing management Nurse leaders should examine ways in which nurses’ work can benefit from system improvements to reduce interruptions that lead to patient safety issues such as treatment delays and loss of concentration.