Serum free light chain analysis in the diagnosis and management of multiple myeloma and related conditions

The serum free light chain (FLC) assay is an important tool in the management of patients with monoclonal gammopathies. MEDLINE^®, the Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Reviews from January 2000 through July 2013, were used as data sources. The available evidence is rather weak. For screening of multiple myeloma and related conditions, the association of the FLC assay with the traditional serum tests avoids urine study. Screening for immunoglobulin light-chain (AL) amyloidosis or other rare syndromes requires the urine examination. FLC measurement is used in the assessment of the risk of progression of precursor diseases to overt myeloma, and for risk stratification in solitary plasmacytoma, multiple myeloma and AL amyloidosis. In patients with oligosecretory myeloma and AL amyloidosis, the quantification of FLC is essential for monitoring and categorization of response to therapy. Further studies with improved design are warranted to strengthen the available evidence.     

UF-1000i全自动尿沉渣分析仪在浆膜腔积液常规检查中的应用

目的:探讨UF-1000i全自动尿液分析仪在浆膜腔积液常规检测中的临床应用价值.方法:对患者浆膜腔积液同时运用传统手工镜检法和UF-1000i全自动尿液分析仪法进行检测,并比较两种方法检测浆膜腔积液中的细胞总数、白细胞数和间皮细胞数.结果:两种方法各细胞间均无显著性差异(P＞0.05).结论:用UF-1000i全自动尿液分析仪检测浆膜腔积液标本简单、易行,检测结果对相关疾病有更好的临床应用价值.     

Dipstick urinalysis findings in children with Plasmodium falciparum in the South Tongu District: A case-control study

Background:

Malaria ranks among the major health and developmental challenges facing some of the poorest countries in tropical and sub-tropical regions across the globe. We determined urinary abnormalities and its relationship with parasite density in children ≤12 years with Plasmodium falciparum infection.

Materials and Methods:

From December 2013 to March 2014, we randomly recruited 116 participants comprising 58 malaria patients (cases) and 58 healthy controls from the Comboni Mission and the Sogakope District Hospitals both in the South Tongu district. Blood was collected for the estimation of hemoglobin and total white blood cells; thick and thin blood films were used for the determination of malaria parasite density. Urine was collected for the measurement of the various biochemical components using the automated urine analyzer. A pretested questionnaire was used to obtain demographic and clinical data.

Results:

Urine protein (P < 0.001), blood (P < 0.001), bilirubin (P < 0.001), urobilinogen (P < 0.001), and ketones (P = 0.001) were significantly higher in individuals with P. falciparum infection than in healthy controls. Proteinuria (P = 0.247; r = 0.155), hematuria (P = 0.142; r = 0.195), bilirubinuria (P = 0.001; r = 0.438), urobilinogenuria (P = 0.876; r = 0.021), and ketonuria (P = 0.136; r = 0.198) were positively correlated with malaria parasite density; however, only bilirubinuria was significantly higher at higher parasitemia.

Conclusion:

Malaria has a significant effect on the chemical composition of urine with bilirubin positively correlated with parasite density. Dipstick urinalysis can be used together with light microscopy in resource-limited malaria-endemic areas to accurately diagnose falciparum malaria infection.     

Interobserver variation in the interpretation of the leucocyte-esterase test by general practitioners

Background: Urinary tract infections are frequent in general practice and the search for a rapid and reliable diagnostic aid continues. Test strips are attractive but need more evaluation in the general practice context.

Objective: To determine the interobserver variation between general practitioners in the interpretation of the leucocyte-esterase test (LE test) to detect leucocytes in urine.

Methods: 37 General practitioners (of whom 85% use these sticks more than once a week) were asked to interpret the LE test (Nephur-test® + leuco Boehringer Mannheim) in 11 urine samples. There were four types of samples: four plainly positive (>500 wbc/ul), one containing 75 wbc/ul, three between 10 and 20 wbc/ul and three negative samples. Evaluation with a spectrophotometric analyser was done twice (MEDITRON® Boehringer): before and after the visual interpretations. The main outcome measure was K for interobserver agreement.

Results: In one of the three negative samples, 26/37 (72%) judged the sample correctly as negative, in the two other negative samples 36/37 (97%) judged them correctly as negative. One in 37 (3%) and 25/37 (68%) of the two slightly positive samples (10-25 wbc) were wrongly interpreted as negative. The k of interobserver agreement in all the observations was 0.68; in the clinically most relevant cut-off point between negative and slightly positive samples (10 wbc/ul), k was 0.54, indicating a modest agreement. In 3 to 68% of the observations, the GP will consider a slightly positive specimen as non-infected. Three to 28% of the negative specimens will be considered as infected. In the four clearly positive specimens the interobserver agreement was between 98 and 100%. In the sample with “nearly 75” leucocytes 24/37 participants (65%) judged that it was “more than 500”.

Conclusion: In a general practice setting the reliability of the LE test should be questioned because of an important interobserver variation in some slightly positive and some negative samples, which are frequently encountered in clinical practice.     

Uf-1000i尿沉渣分析仪检测细菌的性能及对尿路感染的筛查价值

目的评估Uf-1000i尿沉渣分析仪对细菌的检测性能和筛查尿路感染的价值。方法用Uf-1000i尿沉渣分析仪检测患者标本以评估仪器检测细菌的线性和携带污染率。检测200份临床标本并进行尿培养,以临床诊断尿路感染的标准作为诊断尿路感染(UTI)的金标准,计算Uf-1000i尿沉渣分析仪诊断UTI的灵敏度、特异度等参数,并比较Uf-1000i尿沉渣分析仪和尿培养诊断UTI的差异。结果 Uf-1000i尿沉渣分析仪检测细菌在约5~15 000个/μL的范围内取得了良好线性关系,仪器自动冲洗1次时所测的细菌携带污染率为0.026%。对UTI的诊断,Uf-1000i尿沉渣分析仪和尿培养两种方法之间差异有统计学意义(P<0.01)。Uf-1000i尿沉渣分析仪筛选UTI的灵敏度为96.2%(102/106),特异度为46.5%(40/86),阳性预测值为68.9%(102/148),阴性预测值为90.9%(40/44)。结论 Uf-1000i尿沉渣分析仪检测细菌的线性良好,无携带污染,对筛查UTI具有重要价值。     

Current and emerging trends in point-of-care urinalysis tests

ABSTRACT

Introduction: The development of point-of-care testing (POCT) has made clinical diagnostics available, affordable, rapid, and easy to use since the 1990s.The significance of this platform rests on its potential to empower patients to monitor their own health status more frequently, in the convenience of their home, so that diseases can be diagnosed at the earliest possible time-point. Recent advances have expanded traditional formats such as qualitative or semi-quantitative dipsticks and lateral flow immunoassays to newer platforms such as microfluidics and paper-based assays where signals can be measured quantitatively using handheld devices.

Areas covered: This review discusses: (1) working principles and operating mechanisms of both existing and emerging POCT platforms, (2) urine analytes measured using POCT in comparison to the laboratory or clinical ‘gold standard,’ and (3) limitations of existing POCT and expectations of emerging POCT in urinalysis.

Expert opinion: Currently, a variety of biological samples such as urine, saliva, serum, plasma, and other fluids can be applied to POCT for quick diagnosis, especially in resource-limited settings. Emerging platforms will increasingly empower individuals to monitor their health status through frequent urine analysis even from their homes. The impact of these emerging technologies on healthcare is likely to be transformative.     

西安市6000例健康体检者尿液检测结果分析

目的了解西安市健康体检人群中尿液分析异常结果的检出率。方法对6 000例尿液标本进行干化学分析,对各项结果进行分类统计。结果尿液分析阳性(±~++++)检出排序为:白细胞、血、蛋白质、胆红素、酮体、葡萄糖、亚硝酸盐。弱阳性(±或trace)检出排序为:血、白细胞、酮体、蛋白质、胆红素,葡萄糖和亚硝酸盐未发现弱阳性。检测阳性项目总计1 023项,弱阳性项目总计879项。在检测项目中,白细胞、血、蛋白质、亚硝酸盐等阳性率在不同性别和不同年龄间差异有统计学意义(P<0.05)。结论尿液分析是不可缺少的重要检测项目,适用于健康普查及疾病的早期发现。     

Disappointing specificity of the leucocyte-esterase test for the diagnosis of urinary tract infection in general practice

Objectives: To determine the sensitivity and specificity of the leucocyte-esterase test (LE test) as a diagnostic tool in general practice.

Methods: In 249 women consulting their general practitioners for dysuria, both the LE test (Nephur testR + leuco/Boehringer Mannheim) and a culture (UricultRdipslide) were performed on freshly voided urine. The sensitivity and specificity of the LE test were determined with urine culture as standard.

Results: Sensitivity was 96%, specificity only 15.5% (criterion for positivity of the stick: each colour change; positivity for culture: $100,000 colony-forming units (cfu)/ml or every pure culture of Staphylococcus saprophyticus. By lowering the criterion for culture from $100,000 cfu/ml to $10,000 cfu/ml, the specificity increased by only 0.3%. An increase in the specificity to 36% was possible by classifying ‘lightly positive’ dipsticks (10-20 white blood cells/Ml) as negative; the sensitivity then dropped to 87%. Interpretation after one minute also gave a slightly higher specificity and lower sensitivity. Conclusions: In contrast with earlier hospital-based studies, we observed a disappointing specificity of the LE test in daily practice conditions, with the risk of a significant overdiagnosis of urinary tract infection. Earlier diagnostic studies in general practice have shown very diverging results. Our study confirms the most negative ones, questioning the value of the LE test in general practice.