The EFLM European Urinalysis Guideline 2023.

BACKGROUND: The EFLM Task and Finish Group Urinalysis has updated the ECLM European Urinalysis Guidelines (2000) on urinalysis and urine bacterial culture, to improve accuracy of these examinations in European clinical laboratories, and to support diagnostic industry to develop new technologies. RECOMMENDATIONS: Graded recommendations were built in the following areas. MEDICAL NEEDS AND TEST REQUISITION: Strategies of urine testing are described to patients with complicated or uncomplicated urinary tract infection (UTI), and high or low-risk to kidney disease. SPECIMEN COLLECTION: Patient preparation, and urine collection are supported with two quality indicators: contamination rate (cultures), and density of urine (chemistry, particles). CHEMISTRY: Measurements of both urine albumin and α1-microglobulin are recommended for sensitive detection of kidney disease in high-risk patients. Performance specifications are given for urine protein measurements and quality control of multiproperty strip tests. PARTICLES: Procedures for microscopy are reviewed for diagnostic urine particles, including urine bacteria. Technologies in automated particle counting and visual microscopy are updated with advice how to verify new instruments with the reference microscopy. BACTERIOLOGY: Chromogenic agar is recommended as primary medium in urine cultures. Limits of significant growth are reviewed, with an optimised workflow for routine specimens, using leukocyturia to reduce less important antimicrobial susceptibility testing. Automation in bacteriology is encouraged to shorten turn-around times. Matrix assisted laser desorption ionization time-of-flight mass spectrometry is applicable for rapid identification of uropathogens. Aerococcus urinae, A. sanguinicola and Actinotignum schaalii are taken into the list of uropathogens. A reference examination procedure was developed for urine bacterial cultures.

NGAL, L-FABP, and KIM-1 in comparison to established markers of renal dysfunction.

BACKGROUND: New urinary biomarkers like neutrophil gelatinase-associated lipocalin (NGAL), liver-type fatty acid binding protein (L-FABP), and kidney injury molecule-1 (KIM-1) open the opportunity to detect kidney injuries in early stages. Our study aimed at evaluating NGAL, L-FABP, and KIM-1 in comparison to established markers of urine protein differentiation for detection of renal dysfunction. METHODS: On the basis of the PROTIS expert system (for differentiation of glomerulo-/tubulopathy) urine and plasma samples of 263 randomly selected patients were routinely examined (urine: total protein, albumin, IgG, α1-microglobulin, creatinine, and dip stick results for leukocytes, blood, protein, glucose, pH, and nitrite; plasma: creatinine and cystatin C) followed by the analysis of the new urine biomarkers NGAL (CMIA), L-FABP (ECLIA), and KIM-1 (ELISA). RESULTS: Of the three new markers L-FABP showed the highest correlation with α1-microglobulin (r=0.76, p<0.01) and was closest associated with the degree of tubular proteinuria assessed by the PROTIS system. NGAL distinguished the PROTIS proteinuria groups with distinctive tubular proteinurias from the controls as well, but revealed a marked diagnostic influence by leukocyturia. Urinary KIM-1 revealed only a weak diagnostic value for the detection of renal injury. CONCLUSIONS: Urinary NGAL and L-FABP proved to be promising candidates for detecting injuries of the renal tubular system over a broad range of clinical conditions. L-FABP showed a better diagnostic performance and a lower interference by leukocyturia and hematuria than NGAL. Both markers may serve as sensitive tissue injury markers in addition to the established markers of renal functional impairment.

Benefits and limitations of laboratory diagnostic pathways.

Diagnostic pathways are an essential subset of clinical pathways and a logical consequence of DRG-based reimbursement. They combine the principle of stepwise reflex and reflective testing with a management concept that helps to fulfill medical needs with organizational and economic efficacy. The two most common formats describing diagnostic pathways are graphical decision trees on paper and "if…then…else" rules on computers. From a laboratory point of view, diagnostic pathways represent "smart" test profiles, which - in contrast to conventional (inflexible) profiles - are not necessarily worked off completely, but just to a point, where a diagnostic decision can be made. This improves the cost-effectiveness of laboratory testing, while making sure that no essential tests are missed. The paper describes benefits and limitations of diagnostic pathways from a medical, organizational, and economic point of view. Their major advantage is also their major drawback, since they make the diagnostic process on the one hand extremely straight-forward and transparent, while on the other hand oversimplifying the underlying medical decision principles. This may provoke the abuse of their primarily medical intentions for mere economic purposes.

Diagnostic pathways for exclusion and diagnosis of kidney diseases.

In 2006, the German Society for Clinical Chemistry and Laboratory Medicine together with the Society of Nephrology founded a working group with the aim to develop diagnostic pathways for the detection and differentiation of renal diseases. Based on existing recommendations, these pathways may be structured to be a basis for implementation into hospital and laboratory information systems. The present paper describes the contents of these pathways regarding glomerular filtration rate, hematuria, leukocyturia and proteinuria.

Chromosomal imbalances in carcinoma showing thymus-like elements (CASTLE).

Carcinoma showing thymus-like elements (CASTLE) is a rare neoplasm of the thyroid gland resembling lymphoepithelioma-like and squamous cell carcinoma of the thymus and is thought to arise from ectopic thymic tissue within the thyroid gland or rudimentary branchial pouches along the thymic line. Using comparative genomic hybridization (CGH), chromosomal imbalances have been detected in several types of thymomas and thymic carcinomas. To evaluate whether there are hints of an underlying sequence in the pathogenesis of CASTLE analogue to those found in thymomas and thymic carcinomas, we evaluated four of these rare neoplasms for chromosomal imbalances using CGH. The most frequent gains were seen on chromosomal arm 1q (3/4), and losses were most frequently detected on 6p (4/4), 6q (3/4) and 16q (3/4). These CGH data show that CASTLE is characterized by chromosomal imbalances similar to those found in thymomas and thymic carcinomas and indicate a similar sequence in tumour development.

PROTIS: use of combined biomarkers for providing diagnostic information on disease states.

We describe herein PROTIS, a software package that allows for the combination of urine biomarkers (proteins, small molecules, cells) to provide accurate diagnostic information on renal disease states. Such an approach exemplifies the advantage conferred by using multiple markers, and can be generalized for identification of biomarker signatures to separate distinct sample groups.

Clinical role of urinary low molecular weight proteins: their diagnostic and prognostic implications.

In traditional urinalysis, casts in the urinary sediment are the only specific signs of renal tubular injury. When tubulo-interstitial fibrosis became the most predictive sign of renal outcome, tubular enzymes derived from proximal tubular brush border or lysosomes were used as early markers of nephrotoxicity and other tubular dysfunctions. More recently, the increase in low molecular weight proteins in urine, assumed to be freely filtered, was reported to reflect tubular dysfunction. This can have pre-renal, renal and post-renal causes. Among the pre-renal causes, Bence Jones protein (immunoglobulin light chains), myoglobin and haemoglobin are signs of extra-renal diseases. On the other hand, beta(2)-microglobulin, alpha(1)-microglobulin, retinol binding protein and lysozyme were recommended as tubular markers. Because of its lower pre-renal variability and higher stability in urine during storage in the bladder and urinary vessel, alpha(1)-microglobulin proved to be the most valuable in early detection, renal outcome prediction and easy inclusion in routine analytical programmes. In addition, other markers of intra-renal inflammatory processes may help to mirror histological changes occurring in the kidney. Future guidelines should therefore include low molecular protein as a tubular marker.

Bile duct to portal space ratio and ductal plate remnants in liver disease of infants aged less than 1 year.

AIM: To validate the bile duct to portal space ratio as an independent factor useful for the prognosis of neonatal liver disease. METHODS: We assessed the maturation of the intrahepatic bile duct system (IBDS) in 87 consecutive infants aged less than 1 year undergoing non-subcapsular, adequate (at least six portal tracts), liver needle biopsies because of hepatomegaly and/or cholestasis. The maturation of the IBDS was evaluated by immunohistochemistry with an antibody directed to cytokeratin 7 (CK7), a biliary-type intermediate filament of the cytoskeleton, and a schema showing the IBDS remodelling. We used five categories to fit the different patterns of the IBDS remodelling using the ratio between the number of bile ducts and the number of portal tracts (BD/PT) and the presence of abnormal reaction patterns (marked intra-acinar pseudorosettes and/or periportal ductular proliferation): (A) abnormal reaction patterns with any BD/PT; (B) BD/PT = 0; (C) 0.1 < or = BD/PT < 0.5; (D) 0.5 < or = BD/PT < 0.9; and (E) BD/PT > 0.9 (B-E categories: no abnormal reaction patterns). Further, we evaluated cholestasis, portal fibrosis (PF), portal inflammation (PI), giant cell transformation (GCT), and extramedullary haematopoiesis (EMH). RESULTS: We identified A-E categories in 24, 14, 17, 8, and 24 biopsies, respectively. B and C categories were frequently observed in biliary atresia (BA), A category in neonatal hepatitis (NH), A-C categories in paucity of intrahepatic bile ducts (PIBD), and E category in 'other liver diseases' (OLD). Cholestasis, PI, GCT, and EMH were more frequent in A and C, while PF was variably seen in all categories. The lowest survival rate occurred in B (Kaplan-Meier estimator). CONCLUSIONS: (1) Biliary epithelial cell patterns recapitulate the primitive stages of the IBDS maturation; (2) abnormal reaction patterns occur mainly in NH, whilst BD/PT < 0.5 in BA; and (3) lack of intrahepatic bile ducts in infants aged less than 1 year is an adverse prognostic factor independent from aetiology of neonatal liver disease.

How to estimate GFR-serum creatinine, serum cystatin C or equations?

Plasma or serum creatinine is the most commonly used diagnostic marker for the estimation of glomerular filtration rate (GFR) in clinical routine. Due to substantial pre-analytical and analytical interferences and limitations, creatinine cannot be considered accurate. Besides, the diagnostic sensitivity to detect moderate GFR reduction is insufficient. Equations to estimate GFR based on serum creatinine have been introduced, which included anthropometric data to compensate for the limitations of creatinine. Most validated and applied are the MDRD and the Cockcroft-Gault equation for adults, and the Schwartz equation for children. These equations can be calculated at the bedside or issued by the laboratory and provide accurate GFR estimates from 20 to 60 mL/min/1.73 m(2) with good accuracy but moderate to poor bias and precision. Further limiting is the lack of creatinine reference methods and of calibration material. Lately, the low molecular weight protein cystatin C was introduced as a GFR estimate superior to creatinine. In particular, serum cystatin C is sensitive to detect mild GFR reduction between 60 and 90 mL/min/1.73 m(2). However, no reference method and no uniform calibration material exist for cystatin C either. Further limitations are the effect of thyroid dysfunction, of high glucocorticoid doses and potentially the presence of cardiovascular diseases on cystatin C levels. To evade these obstacles and to further improve GFR estimation, cystatin C-based equations have been proposed, which seem to be superior to creatinine-based ones. However, this issue requires further evaluation. We propose a panel of GFR markers to facilitate the detection of reduced GFR at various stages and in different populations; this however needs to be extended and refined in the near future. In principle, clinicians should be aware of the limitations of and cautioned not to overrate estimated GFR by single markers or calculated by equations and should not entirely rely on GFR estimates to make precise clinical decisions.

A new concept for detection of Bence Jones proteinuria in patients with monoclonal gammopathy.

Bence Jones (free light chain-FLC) proteinuria is usually detected by immunofixation electrophoresis (IFE) of urine. With a new, automated immunoassay, it is now possible to quantify FLC in serum and urine. In the present study, we compared different routine methods for monoclonal FLC screening. From our results we conclude that the measurement of FLC in serum is highly sensitive and should replace urine tests. Additionally, possible kidney dysfunction, caused by nephrotoxicity of FLC, should be assessed by urine protein analysis and cystatin C measurements.

Serum hyaluronate correlates with histological progression in alcoholic liver disease.

OBJECTIVES: Chronic alcohol consumption may lead to the development of liver cirrhosis. Serum concentrations of hyaluronate were suggested as a predictor in chronic liver disease, but its power to distinguish between severity of fibrosis and inflammation had not been assessed. In order to evaluate hyaluronate as a marker to detect early stages of alcoholic liver disease and to establish a possible correlation with hepatic histology, serum concentrations were measured by radioimmunoassay in 87 patients with biopsy-proven fatty liver, fatty liver and mild fibrosis, fatty liver and inflammation, severe fibrosis and inflammation, and cirrhosis, and in 12 non-alcoholic control subjects. In addition, serum hyaluronate was determined in 40 non-cirrhotic alcoholic patients with either a normal serum aspartate aminotransferase (AST) or an AST elevated at least two-fold. RESULTS: Serum hyaluronate increased significantly with advanced stages of alcoholic liver disease, while levels in patients with fatty liver were elevated only slightly without reaching significance. Hyaluronate correlated well with histological stage and was highly sensitive for detecting fibrosis in general and perivenular fibrosis as an indicator of progression to cirrhosis. Hyaluronate levels were not influenced by AST levels. CONCLUSION: Serum hyaluronate is a good predictor of the presence of even moderate hepatic fibrosis in alcoholic liver disease, justifying its clinical use to assess morphological alterations of the liver in alcoholics.

Histologic classification of thymic epithelial tumors: comparison of established classification schemes.

The object of our multicenter retrospective study was to compare the new histologic World Health Organization (WHO) classification and the classical histologic Bernatz classification in terms of interobserver agreement and prognostic importance. The influence of coexisting diseases was also analyzed using the Charlson score. We evaluated 218 patients from 5 different hospitals who were treated between 1967 and 1998. The statistical methods of analysis included Kaplan-Meier estimates of survival curves and the application of Cox proportional hazards models to identify sets of prognostic factors for survival. Interobserver agreement was assessed by kappa coefficients. For both WHO and Bernatz classifications, interobserver agreement was good (weighted kappa > 0.87). However, the subdiversification of the "bioactive" WHO subgroup (B1, B2, B3) resulted in an interobserver agreement of only 0.49 within this group. In multivariable models, both the WHO classification and the Bernatz classification including carcinomas showed similar prognostic capabilities. The B3 type in the WHO classification and the predominantly epithelial type in the Bernatz classification had an intermediate prognostic ranking in comparison with the carcinomas and with the other subgroups. For both classifications, further simplification and subclassification into 3 subgroups led to classes with good discriminative power in respect to survival. In addition, very good interobserver agreement was observed in the simplified classifications. Comorbidity, sex, age of the patient and lymphofollicular hyperplasia had no major influence on overall survival. Both classifications showed similar prognostic power. Interobserver agreement of the type B subgroups was only moderate. By simplification of the classifications, subgroups with distinct survival could be identified.

Single nucleotide insertion in the 5'-untranslated region of hepatitis C virus with clearance of the viral RNA in a liver transplant recipient during acute hepatitis B virus superinfection.

Hepatitis C virus (HCV) infection is an important etiology in patients undergoing orthotopic liver transplantation (OLT) world-wide. Antiviral therapy-related clearance of HCV RNA may occur both in patients with chronic HCV infection and in transplanted patients for HCV-related liver cirrhosis, but the role of the 5'-untranslated region (UTR) of HCV containing the internal ribosome entry site (IRES), which directs the translation of the viral open reading frame has not hitherto been evaluated. We studied the 5'-UTR in an HCV-infected recipient of a liver graft that showed spontaneous clearance of HCV RNA during an acute hepatitis B virus (HBV) superinfection. Sequencing of the 5'-UTR of HCV showed a nucleotide A insertion at position 193 of the IRES.