POCT血糖仪与生化分析仪血糖水平检测比对方案的研究

目的比对北京市朝阳区妇儿医院临床科室床旁检验(POCT)血糖仪与日立生化分析仪7600的精密度及准确性,探讨适合基层医院的比对方案。方法从临床采用的强生公司NOVA Stat-Strip血糖仪10台中随机抽取1台,连续测定高、低2个血糖水平的抗凝全血各20次,计算精密度。选取20例不同血糖水平的抗凝全血,分别在10台NOVA Stat-Strip血糖仪与日立生化分析仪7600配对比对。绘制散点图并拟合回归方程,进行配对资料t检验。结果精密度低水平(血糖水平小于5.50mmol/L)血糖仪的标准差为0.16mmol/L,小于GB/T19634-2005(B)标准要求的标准差(0.42mmol/L),高水平(血糖水平大于或等于5.50mmol/L)血糖仪的变异系数为3.4%,小于GB/T19634-2005(B)标准要求的变异系数(7.5%)。10台血糖仪与日立生化分析仪7600相关系数均大于0.95,相关性好,配对t检验,差异有统计学意义(P0.05)。根据GB/T19634-2005(B)标准,10台血糖仪准确性良好。结论10台血糖仪与日立生化分析仪7600血糖水平检测比对结果的精密度及准确度符合GB/T19634-2005(B)标准要求。比对方案简单易行,可用于临床。     

便携式血糖仪与全自动生化分析仪检测结果比对分析

目的 了解该院临床科室使用的床旁检测(POCT)血糖仪的准确度和精密度.方法 以经乙二胺四乙酸二钾抗凝的健康者静脉血标本为检测对象,对不同品牌血糖仪与全自动生化分析仪检测结果进行比对分析.结果 罗氏便携式血糖仪准确度和精密度合格率均达到96.3%;强生血糖仪准确度合格率达56.3%,精密度合格率均达到62.5%;美国雅培血糖仪精密度和准确度均不合格.结论 POCT血糖仪准确度和精密度越高,其检测结果与全自动生化仪检测结果的偏差越小.     

床旁检验血糖仪与生化分析仪测定血糖的比对分析

目的 对床旁检验(POCT)血糖仪与生化分析仪血糖结果准确度进行比对分析.方法 每年2次分别用50份样品对中山市博爱医院血糖仪和生化分析仪同时检测血糖,进行准确度比对分析.结果 血糖仪的合格率明显逐年上升;血糖仪的不合格台数和不合格样品份数也明显逐年下降.结论 每年2次POCT血糖仪与生化分析仪血糖结果准确度比对对加强血糖仪的管理十分有效,可明显提高血糖仪的准确度,必须坚持开展.     

床旁检验血糖仪与生化分析仪血糖测定结果比对分析

目的对中山医院床旁检验（POCT）血糖仪与全自动生化分析仪血糖测定结果进行比对分析和偏倚评估,以保证血糖仪检测结果的一致性。方法参照《便携式葡萄糖仪血液葡萄糖测定指南》,采集肝素钠抗凝静脉血10份,血糖水平分布在3.20～25.81mmol/L。在POCT血糖仪和生化分析仪上重复测定3次,以生化仪为靶仪器,计算相对偏倚。结果 42台血糖仪中的38台与生化分析仪测定值相对偏倚在1%～13%,符合要求。结论通过对中山医院POCT血糖仪与生化分析仪血糖测定结果的比对和偏倚评估,评价血糖仪检测的准确性,以更好地规范医院床旁血糖仪的使用。     

拜耳ADVIA 1200型全自动生化仪装机测试及与非配套系统的比较分析

目的拜耳ADVIA1200型全自动生化仪装机测试。测试内容包括精密度、正确性及配套系统与现用非配套分析系统进行相关性比对，为探讨实验室检验结果的可溯源性提供数据。方法精密度评价参考NCCLS文件EP5-A进行；每天分2批测定样本，各批试验间隔至少在3h以上。每批测定2个浓度样本，每个样本重复测定20次。方法学比较采用NC—CLS文件EP9-A进行，连续5天每天测定（各项目室内质控结果在允许范围内）8例病人血清（测双份取平均值），进行两方法检验结果之间的比较。检测各项目质控结果与靶值比较。进行准确性分析。结果拜耳ADVIA120050％以上的低值质控的批内精密度小于1％，部分项目的总不精密度在2．0％左右，最大的不精密为ALT的4．44％；大多数项目的偏离度在1％～4％。使用非配套试剂与配套系统比较大部分项目相关性良好（r^2〉0．95）。结论检测数据显示不同项目的精密度、准确性。通过非配套与配套试剂系统的比对，为实验室选择开放试剂及实验室数据的可溯源性提供了参考数据。     

床旁检验的应用

随着检验医学的飞速发展，为了更加方便患者，大量高效、快速、操作简单、设备轻便的小型仪器越来越多地被各医院临床科室及社区门诊所应用，即床旁检验方法随之诞生，床旁检验（POCT）是一种快速、简便的筛查方法，主要应用于对疾病的及时监控和作为治疗过程中的用药剂量调控的参考依据。     

临床检验分析方法精密度要求的重新评价

临床检验对分析方法不精密度的一般要求是，方法两部的标准差（ｓ）小于允许分析误差（ＡＡＥ）（即是２ｓ〈ＡＡＥ）。然而，当最低限度地满足这一标准时，常用的控制方法对医学上重要的误差不能可靠地检出。统计控制方法功效函数的研究表明，医学上重要误差大小必须至少是３ｓ时，才能落在功效的平台附近，且易由常用控制方法检出。然而，对于方法刚好满足２ｓ〈ＡＡＥ精密度标准，医学上重要误差将落在功效函数曲线的上升部位，且     

即刻床旁血气分析仪与中心实验室血气分析仪的一致性评价

目的 评价即刻床旁血气分析仪与实验医学科临床生化实验室血气分析仪测定结果的一致性.方法 参考医疗机构临床实验室管理办法和临床实验室标准协会(CLSI)提出的比对建议设计比对方案,对血气分析直接测定的指标pH值,氧分压(PO2)和二氧化碳分压(PCO2)进行分次比对,使用SPSS11.0软件进行F检验,分析多台仪器之间差异,并参照各项目的 临床总允许误差(TEa).结果 三个项目中,每台仪器测定结果间的差异均无统计学意义(P>0.05),即刻床旁血气分析仪与临床生化实验室血气分析仪PCO2的测定结果绝对偏差小于1/2 TEa,pH值比对结果绝对偏差小于TEa,PO2测定结果的绝对差值大部分不在TEa范围内.结论 pH值和PO2存在系统偏差,需调试即刻床旁检测仪并对病房使用即刻床旁检测仪器相关人员进行规范化培训,才能有效控制分析前的变异,以保证POCT与中心实验室测定结果的一致性.     

Point-of-care and standard laboratory coagulation testing during cardiovascular surgery: balancing reliability and timeliness

Objective. The use of point-of-care technology has increased faster than efforts to validate its effectiveness compared to standard laboratory testing modalities. To address this issue with a current point-of-care coagulation system (HEMOCHRON® Jr, International Technidyne Corporation (ITC), Edison, NJ), we designed a study to test the hypothesis that data obtained from point-of-care coagulation equipment correlates with data obtained from standard laboratory coagulation equipment. One of the potential advantages gained using point-of-care testing is the ability to obtain more rapid results. To address this issue, turnaround time, defined as the elapsed time (in minutes) from when the sample was acquired from the patient until the investigators knew the results, was also determined. Methods. Following Human Investigation Committee approval and informed consent, a prospective study was conducted to compare results obtained from point-of-care coagulation equipment with those results obtained from standard laboratory coagulation equipment. The study was performed in three groups of patients undergoing cardiovascular surgery, each requiring different levels of anticoagulation. Results. Of the 83 patients who met the inclusion criteria, the correlation (combining data from groups 1–3) between results obtained from point-of-care and standard laboratory prothrombin time was r = 0.867, p < 0.001. The correlation (group 3) between point-of-care and standard laboratory international normalized ratio was r = 0.943, p < 0.001. The correlation (combining data from groups 1 & 2) between point-of-care and standard laboratory activated partial thromboplastin time was r = 0.825, p < 0.001. Median turnaround time for the standard laboratory was 90 minutes, with a mean turnaround time of 74 to 78 minutes, depending upon the group. In contrast, the median turnaround time for point-of-care testing was two minutes and 14 seconds. Conclusions.The results from this study population reveal that data obtained from point-of-care prothrombin time, international normalized ratio and activated partial thromboplastin time results correlate with results obtained from standard laboratory coagulation testing. The value of obtaining reliable results in a timely fashion offers a potential advantage for point-of-care testing in clinical situations, such as in the operating room, where saving time may translate into financial savings.     

Effect of Point-of-care Influenza Testing on Management of Febrile Children

Objectives To determine the effect of point‐of‐care testing (POCT) for influenza on the physician management of febrile children who are at risk for serious bacterial illness (SBI) on the basis of age and temperature and who are presenting to a pediatric emergency department (ED) during an influenza outbreak. Methods Patients 2–3 months of age with temperature of ≥38°C and patients 3–24 months of age with temperature of ≥39°C who were presenting to a pediatric ED during an influenza outbreak were enrolled into a prospective, quasi‐randomized, controlled trial. Influenza testing was performed on enrolled patients by either the POCT or the standard‐testing (ST) methods. The two groups were compared in terms of laboratory testing, chest radiography, antibiotic use, visit‐associated costs, pediatric ED lengths of stay, inpatient admission, and return visits to the pediatric ED. Similar analyses also were performed on the resulting subgroups of patients on the basis of method of testing (POCT or ST) and test result (positive or negative). Results Of 767 eligible patients, 700 (91%) completed the study. No significant differences were demonstrated between the POCT and ST groups with respect to laboratory tests ordered, chest radiographs obtained, antibiotic administration, inpatient admission, return visits to the pediatric ED, lengths of stay, or visit‐associated costs. In the subgroup analysis, the adjusted odds ratios (ORs) for blood culture in influenza test–positive to –negative patients were 0.59 and 0.71 in the POCT and ST groups, respectively (p = 0.088). The adjusted ORs for urine culture in influenza test–positive to –negative patients were 0.46 and 0.67 in the POCT and ST groups, respectively (p = 0.005). Conclusions When using a strategy of performing influenza testing on all patients at risk for SBI who presented to a pediatric ED during an influenza outbreak, the method of testing (POCT or ST) did not appear to significantly alter physician management, cost, or length of stay in the pediatric ED. However, if the interaction of the method of testing and the test result (positive or negative) were considered, a positive POCT for influenza was associated with a significant reduction in orders for urinalyses and urine cultures.     

“Hook-like Effect” Causes False-negative Point-of-care Urine Pregnancy Testing in Emergency Patients

Background

Failure to detect pregnancy in the emergency department (ED) can have important consequences. Urine human chorionic gonadotropin (uhCG) point-of-care (POC) assays are valued for rapidly detecting early pregnancy with high sensitivity. However, under certain conditions, POC uhCG tests can fail to detect pregnancy.

Objectives

In investigating a series of late first-trimester false-negative pregnancy tests in our ED, a novel and distinct causative phenomenon was recently elucidated in our institution. We discuss uhCG POC tests, review our false-negative rate, and describe mechanisms for false negatives and potential remedies.

Discussion

The false-negative POC uhCG rate is very low, but in the setting of a large volume of tests, the numbers are worth consideration. In positive uhCG POC tests, free and fixed antibodies bind hCG to form a “sandwich”; hCG is present in several variant forms that change in their concentrations at different stages of pregnancy. When in excess, intact hCG can saturate the antibodies, preventing sandwich formation (hook effect phenomenon). Some assays may include an antibody that does not recognize certain variants present in later stages of pregnancy. When this variant is in excess, it can bind one antibody avidly and the other not at all, resulting in a false-negative test (hook-like phenomenon). In both situations, dilution is key to an accurate test.

Conclusions

Manufacturers should consider that uhCG tests are routinely used at many stages of pregnancy. Characterizing uhCG variants recognized by their tests and eliminating lot-to-lot variability may help improve uhCG test performance. Clinicians need to be aware of and familiarize themselves with the limitations of the specific type of uhCG POC tests used in their practice, recognizing that under certain circumstances, false-negative tests can occur.     

External quality assessment in the measurement of haemoglobin by blood gas analysers in Belgium

Objective. The Belgian national External Quality Assessment Scheme (EQAS) for haematology organized a survey to assess the reliability of haemoglobin (Hb) measurements with the blood gas analysers (BGAs) currently available in Belgian hospitals. Material and methods. All hospital laboratories received two specimens of fresh EDTA anticoagulated whole blood and were asked to determine the Hb concentration using both the conventional haematology analyser (HA) and all BGAs in the hospital. Ninety‐seven hospital laboratories participated in the study and a total of 166 results were reported. The BGAs used (grouped according to technology) were Rapidlab 845, 855, 865 (Bayer 1, n = 41), Rapidlab 1245, 1265, Rapidpoint 405 (Bayer 2, n = 19), GEM Premier 3000 (Instrumentation Laboratory, IL, n = 13), ABL 500 and 600 series (Radiometer 1, n = 13), ABL 700 and 800 series (Radiometer 2, n = 35), Omni C, S5 (Roche 1, n = 7), Omni 3, 6, 9, S2, S4, S6 (Roche 2, n = 21). Results. For the BGAs from Bayer, Radiometer and Roche, interlaboratory variation ranged from 0.6?% to 4.1?%, indicating good precision and close agreement between centres. A significant negative bias observed on the GEM Premier 3000 using the EDTA anticoagulated blood samples did not appear to be present in fresh heparinized whole blood samples. There was no significant difference in imprecision and bias between Hb measurements on BGA situated in and outside the central laboratory.     

对离子选择电极法电解质分析仪性能评价指标的研究

目的建立一种电解质分析仪的评价标准,提高电解质分析仪检测结果的可比性。方法对凯特电解质分析仪的精密度、线性、稳定性、携带污染率等指标进行了评价。结果K ,Na ,Cl-各分析元素的精密度最大变异系数(CV)为1.11%,线性离散百分误差D值最大为2.0%,波动百分比S最大值为1.33%。从低浓度到高浓度的携带污染率(CLH)最大值为1.28%,从高浓度到低浓度的携带污染率(CHL)最大值为1.15%。结论电解质分析仪的性能评价指标需要进一步完善,使其在实际工作中具有可执行性;实验室应建立离子选择电极(ISE)直接法检测K ,Na ,Cl-的参考范围,这对临床的应用非常重要。     

Comparison of the diagnostic characteristics of two B-type natriuretic peptide point-of-care devices

Background

B-type natriuretic peptide (BNP) is used to diagnose heart failure (HF).

Objective

To compare the accuracy of two commercially available point-of-care (POC) devices for measuring B-type natriuretic peptide (BNP) in emergency department (ED) patients with suspected heart failure using the central laboratory testing results as the criterion standard.

Methods

Venous blood samples were collected from adults with suspected heart failure and split into three samples for BNP analysis: central laboratory (Siemens ADIVA Centaur; Siemens, Deerfield, IL), Triage BNP POC device (Biosite, San Diego, CA), and i-STAT BNP POC device (Abbott, East Windsor, NJ). The criterion standard for BNP levels was the central laboratory.

Results

Two hundred fifty patients were enrolled. Mean (SD) age was 70.7 (13.8) years; 200 (80%) were over age 55 years; 146 (58.4%) were male. A final hospital discharge diagnosis of heart failure was made in 108 (42%) patients. The i-STAT system yielded a result within a median of 9 min (interquartile range [IQR] 9–10 min). The Triage device yielded a result within a median of 19 min (IQR 15–22 min); p < 0.001. The device failure rate for the central laboratory (8 failures, 3.2%) was significantly higher than that of the i-STAT device (1 failure, 0.4%, p = 0.04), but not statistically different than the Triage device (3 failures, 1.2%). Neither the Triage nor the i-STAT were statistically different than the central laboratory result in terms of sensitivity; the i-STAT was less specific than the Triage result (p = 0.003). The area under the curve for the Triage device was 0.95 (95% confidence interval [CI] 0.91–0.98), whereas the area under the curve for the i-STAT device was 0.98 (95% CI 0.96–0.99; p < 0.01).

Conclusions

Both POC devices tested were accurate and rarely failed; however, the i-STAT was faster with single use.     

Point-of-care ultrasound in the diagnosis of neonatal cerebral sinovenous thrombosis

Cerebral sinovenous thrombosis (CSVT) mostly affects sick neonates in the neonatal intensive care unit (NICU) with predisposing or underlying conditions. The clinical presentation is nonspecific which often leads to a delayed or missed diagnosis. Point-of-care ultrasound (POCUS) use in the NICU is rapidly increasing. One of the main uses of neonatologist-performed POCUS is cranial ultrasound which permits diagnosis and monitoring of neurological disease at the bedside. We present the case of a neonate with a complex clinical situation where cranial POCUS permitted a prompt diagnosis and treatment of severe CSVT by imaging the transverse sinuses through the mastoid fontanelle.     

The individual systematic difference between CoaguChek and STA-SPA+

Using CoaguChek to measure PT-INR and comparing the results with those from the hospital laboratory, some patients get consistent results while others do not. The extent of this problem is unknown. Our study aimed to quantify the between-subject variation of the systematic PT-INR difference between CoaguChek and a hospital laboratory method. We used register data with PT-INR results from both CoaguChek and a hospital laboratory method (STA-SPA+) in samples taken simultaneously from 108 patients. After excluding five patients with outlying results, we used mixed-effects models to estimate individual slopes and intercepts to describe the systematic relationship between the two methods for each patient, and calculated the fraction of patients having a systematic difference greater than 0.3 INR units. The included 103 patients had from 3 to 16, median seven data pairs measured over a time span from 15 to 2319, median 234 days. The mean of individual slopes was 1.113, with a standard deviation of 0.137. Corresponding values for the intercept were –0.151 and 0.208, respectively. Adjusted for the average systematic difference, the proportion of patients with a systematic difference greater than 0.3 INR units increased from 15% at a PT-INR level of 2.5 to 50% at a PT-INR level of 4. The systematic difference between CoaguChek and STA-SPA?+?varies considerably between patients. This precludes using a single, common formula to make the CoaguChek results directly comparable to the results from the hospital laboratory.     

BECKMAN DxI 800全自动 化学发光仪检测泌乳素的性能验证

目的 对BECKMAN DxI 800全自动化学发光仪检测泌乳素(PRL)的分析性能进行验证。方法 参照美国临床实验室标准化协会(NCCLS)的文件,选取病人血清和质控室间质评质控品,对PRL的批内精密度、批间精密度、准确度、线性范围等方面进行验证。结果 PRL的批内和批间精密度CV值均小于厂家声明的CV值,在允许范围内; PRL线性范围验证结果显示,a值为1.011 4,r值为0.997 4,均在仪器要求范围内,并具有良好的线性; PRL准确度验证结果显示,测定5份室间质评的检测结果与“靶值”的偏倚为-1.18%～-7.78%,均在室间质评的测量范围之内。结论 BECKMAN DxI 800全自动化学发光仪测定PRL在精密度、准确度、线性范围等性能指标均在仪器要求范围内,符合要求,可应用于临床检测。     

The microINR portable coagulometer: analytical quality and user-friendliness of a PT (INR) point-of-care instrument

Regular measurement of prothrombin time as an international normalized ratio PT (INR) is mandatory for optimal and safe use of warfarin. Scandinavian evaluation of laboratory equipment for primary health care (SKUP) evaluated the microINR portable coagulometer (microINR^®) (iLine Microsystems S.L., Spain) for measurement of PT (INR). Analytical quality and user-friendliness were evaluated under optimal conditions at an accredited hospital laboratory and at two primary health care centres (PHCCs). Patients were recruited at the outpatient clinic of the Laboratory of Medical Biochemistry, St Olav’s University Hospital, Trondheim, Norway (n?=?98) and from two PHCCs (n?=?88). Venous blood samples were analyzed under optimal conditions on the STA-R^®Evolution with STA-SPA?+?reagent (Stago, France) (Owren method), and the results were compared to capillary measurements on the microINR^®. The imprecision of the microINR^® was 6% (90% CI: 5.3–7.0%) and 6.3% (90% CI: 5.1–8.3) in the outpatient clinic and PHCC2, respectively for INR ≥2.5. The microINR^® did not meet the SKUP quality requirement for imprecision ≤5.0%. For INR <2.5 at PHCC2 and at both levels in PHCC1, CV% was ≤5.0. The accuracy fulfilled the SKUP quality goal in both outpatient clinic and PHCCs. User-friendliness of the operation manual was rated as intermediate, defined by SKUP as neutral ratings assessed as neither good nor bad. Operation facilities was rated unsatisfactory, and time factors satisfactory. In conclusion, quality requirements for imprecision were not met. The SKUP criteria for accuracy was fulfilled both at the hospital and at the PHCCs. The user-friendliness was rated intermediate.