Serum albumin: Accuracy and clinical use

Prognostic value of lactate dehydrogenase, serum albumin and the lactate dehydrogenase/albumin ratio in patients with diffuse large B-cell lymphoma

OBJECTIVE

To investigate the prognostic value of lactate dehydrogenase (LDH), serum albumin (ALB) and the lactate dehydrogenase/albumin ratio (LAR) in diffuse large B-cell lymphoma (DLBCL) before primary treatment.

METHODS

The clinical data of 212 primary adult DLBCL patients admitted to the First People's Hospital of Lianyungang from January 2017 to December 2022 were analyzed retrospectively. The optimal cutoff values of LDH, ALB, and LAR were determined using ROC curves. Survival curves of LDH, ALB, and LAR were plotted and analyzed using the Cox regression model and Kaplan-Meier method with the log-rank test.

RESULTS

Among the 212 patients admitted, the study derived the optimal cutoff values for ALB, LDH, and LAR as 38, 301, and 6, respectively. The Kaplan-Meier method and log-rank test analysis indicated a significant association between lower ALB levels, elevated LDH levels, elevated LAR levels, and shorter overall survival (OS) and progression-free survival (PFS) (P < 0.05). Additionally, the critical values of ALB and LDH were grouped into three categories. The differences in OS and PFS among these three groups were statistically significant (P < 0.05). Cox multifactorial analysis revealed that the LAR was an independent factor influencing the prognosis of OS and PFS, with a higher prognostic value than LDH and ALB alone.

CONCLUSION

Decreased ALB levels and elevated LDH and LAR levels at the time of initial diagnosis are indicative of a poor prognosis in DLBCL patients. Furthermore, the study highlighted that the LAR has a higher prognostic value than LDH and ALB alone.

Feasibility of Metrological Traceability Implementation Using the Joint Committee on Traceability in Laboratory Medicine Database Entries Including the Fulfillment of "Fit-for-Purpose" Maximum Allowable Measurement Uncertainty

BACKGROUND

In previous publications, the Task Force on Reference Measurement System Implementation proposed a procedural approach combining a critical review of entries available in the Joint Committee on Traceability in Laboratory Medicine (JCTLM) database with a comparison of this information against analytical performance specifications for measurement uncertainty (MU) and applied it to a group of 13 measurands.

CONTENT

Here we applied this approach to 17 additional measurands, of which measurements are frequently requested. The aims of the study were (a) to describe the main characteristics for implementing traceability and the potential to fulfill the maximum allowable MU (MAU) at the clinical sample level of certified reference materials and reference measurement procedures listed in the JCTLM database; (b) to discuss limitations and obstacles, if any, to the achievement of the required quality of laboratory measurements; and (c) to provide a gap analysis by highlighting what is still missing in the database. Results were integrated with those obtained in the previous study, therefore offering an overview of where we are and what is still missing in the practical application of the metrological traceability concept to 30 common biochemical tests employed in laboratory medicine.

SUMMARY

Our analysis shows that for 28 out of 30 measurands, conditions exist to correctly implement metrological traceability to the International System of units and fulfill at least the MAU of the minimum quality level derived according to internationally recommended models. For 2 measurands (serum albumin and chloride), further improvements in MU of higher-order references would be necessary.

Analytical performance specifications for combined uncertainty budget in the implementation of metrological traceability

In addition to the correct implementation of calibration traceability, the definition and fulfillment of maximum allowable measurement uncertainty (MAU) are essential in assuring that laboratory measurements are clinically usable. Across the entire calibration hierarchy, three major contributors to the measurement uncertainty (MU) budget are identified, starting with the higher-order reference providers, extending through the in vitro diagnostic (IVD) manufacturers and their processes for assigning calibrator values, and ending with medical laboratories generating the random variability of results reported to clinicians. To understand if it is possible to achieve MAU and, consequently, to fix the possible drawbacks, the definition of combined MU budget limits across the entire calibration hierarchy has a central role. In particular, quality specifications for MU of reference and commercial calibrator materials should be defined according to the MAU on clinical samples. All involved stakeholders (i.e., higher-order reference providers, IVD manufacturers, medical laboratories) should be prepared to improve their performance whenever the clinical application of the test is made questionable by the failure to achieve MAU.

Albumin determined by bromocresol green leads to erroneous results in routine evaluation of patients with chronic kidney disease

OBJECTIVES

Measurement of plasma albumin is pivotal for clinical decision-making in patients with chronic kidney disease (CKD). Routinely used methods as bromocresol green (BCG) and bromocresol purple (BCP) can suffer from aselectivity, but the impact of aselectivity on the accuracy of plasma albumin results of CKD-patients is still unknown. Therefore, we evaluated the performance of BCG-, BCP- and JCTLM-endorsed immunological methods in patients with various stages of CKD.

METHODS

We evaluated the performance of commonly used albumin methods in patients with CKD stages G1 through G5, the latter divided in two groups based on whether they received hemodialysis treatment. In total, 163 patient plasma samples were measured at 14 laboratories, on six different BCG and BCP-platforms, and four different immunological platforms. The results were compared with an ERM-DA-470k-corrected nephelometric assay. The implications on outcome is evaluated by the proportion of patient results <38 g/L for the diagnosis of protein energy wasting.

RESULTS

Albumin results determined with BCP- and immunological methods showed the best agreement with the target value (92.7 and 86.2 %, respectively vs. 66.7 % for BCG, namely due to overestimation). The relative agreement of each method with the target value was platform-dependent, with larger variability in agreement between platforms noted for BCG and immunological methods (3.2-4.6 and 2.6-5.3 %) as opposed to BCP (0.7-1.5 %). The stage of CKD had similar effects on the variability in agreement for the three method-groups (0.6-1.8 % vs. 0.7-1.5 % vs. 0.4-1.6 %). The differences between methods cause discrepancies in clinical decision-making, as structurally fewer patients were diagnosed with protein energy wasting upon using BCG-based albumin results.

CONCLUSIONS

Our study shows that BCP is fit for the intended use to measure plasma albumin levels in CKD patients from all stages, including patients on hemodialysis. In contrast, most BCG-based platforms falsely overestimate the plasma albumin concentration.

Mild cognitive impairment in type 2 diabetes is associated with fibrinogen-to-albumin ratios

Background

Cognitive impairment is the main manifestation of diabetes central neuropathy. Currently, there is no effective dementia treatment; early diagnosis and treatment are particularly crucial. Inflammation index fibrinogen-to-albumin ratio (FAR) has been shown to predict complications of type 2 diabetes (diabetic kidney disease and diabetes-related arteriosclerosis), but its relationship with mild cognitive impairment (MCI) in type 2 diabetes (T2D) is undetermined. In this study, we examined the association between the FAR and mild cognitive impairment in type 2 diabetes.

Methods

This is a retrospective and cross-sectional study. From January 2022 to December 2022, we have retrieved 328 inpatient medical records for T2D patients hospitalized at the First Hospital of Harbin Medical University from the hospital's electronic system. Subjects' cognitive function was assessed and grouped by the MoCA scales. Subjects' demographic and various laboratory indicators were collected. Using Spearman's bivariate correlation analysis, the FAR and other clinical variables were analyzed for association strength. A multiple linear regression analysis was conducted to determine the independent relationship between FAR and MoCA scores. Multivariate logistic regression was used to analyze the independent relationship between FAR and MCI. The capacity of the FAR to detect MCI was carried using receiver operating characteristic (ROC) analysis.

Results

The included participants' (n = 328; 61.9% male) mean age was 52.62 ± 10.92 years. MoCA scores and MCI prevalence significantly differed (p < 0.05) between the four subgroups of FAR quartiles. The FAR and the MoCA score were significantly negatively correlated in the entire population (p < 0.05). Based on the multiple linear regression analysis, lnFAR and lnMoCA are significantly correlated (β = -0.449, t = -8.21, p < 0.05, R2 = 0.469). In multivariate logistic regression analysis, FAR and MCI were independently correlated after adjusting for covariates (OR 95% CI 34.70 [13.90-86.66]). Finally, the analysis of receptor working characteristics shows that the optimal FAR cut-off value was 0.08 (sensitivity: 95.81%, specificity: 84.47%) for detecting MCI in type 2 diabetes.

Conclusion

In type 2 diabetes, the FAR was positive associations with MCI and negative associations with MoCA score. The high FAR was associated with an increased risk of MCI. FAR maybe a appropriate indicator of MCI risk for type 2 diabetes.

Impedimetric immunosensor for microalbuminuria based on a WS2/Au water-phase assembled nanocomposite

An electrochemical impedimetric biosensor for human serum albumin (HSA) determination is proposed. The biosensor is based on water-phase assembled nanocomposites made of 2D WS₂ nanoflakes and Au nanoparticles (AuNPs). The WS₂ has been produced using a liquid-phase exfoliation strategy assisted by sodium cholate, obtaining a water-stable suspension that allowed the straightforward decoration with AuNPs directly in the aqueous phase. The resulting WS₂/Au nanocomposite has been characterized by atomic force microscopy and Raman spectroscopy and, then, employed to modify screen-printed electrodes. Good electron-transfer features have been achieved. An electrochemical immunosensing platform has been assembled exploiting cysteamine-glutaraldehyde covalent chemistry for antibody (Ab) immobilization. The resulting immunosensor exhibited good sensitivity for HSA detection (LOD = 2 ng mL^-1), with extended linear range (0.005 - 100 µg mL^-1), providing a useful analytical tool for HSA determination in urine at relevant clinical ranges for microalbuminuria screening. The HSA quantification in human urine samples resulted in recoveries from 91.8 to 112.4% and was also reproducible (RSD < 7.5%, n = 3), with marked selectivity. This nanocomposite, thanks to the reliable performance and the ease of the assembling strategy, is a promising alternative for electrochemical immunosensing of health relevant markers.

Coelenterazine Indicators for the Specific Imaging of Human and Bovine Serum Albumins

Albumin assays in serum are important for the prognostic assessment of many life-threatening diseases, such as heart failure, liver disease, malnutrition, inflammatory bowel disease, infections, and kidney disease. In this study, synthetic coelenterazine (CTZ) indicators are developed to quantitatively illuminate human and bovine serum albumins (HSA and BSA) with high specificity. Their functional groups were chemically modified to specifically emit luminescence with HSA and BSA. The CTZ indicators were characterized by assaying the most abundant serum proteins and found that the CTZ indicators S6 and S6h were highly specific to HSA and BSA, respectively. Their colors were dramatically converted from blue, peaked at 480 nm, to yellowish green, peaked at 535 nm, according to the HSA-BSA mixing ratios, wherein the origins and mixing levels of the albumins can be easily determined by their colors and peak positions. The kinetic properties of HSA and BSA were investigated in detail, confirming that the serum albumins catalyze the CTZ indicators, which act as pseudo-luciferases. The catalytic reactions were efficiently inhibited by specific inhibitors, blocking the drug-binding sites I and II of HSA and BSA. Finally, the utility of the CTZ indicators was demonstrated through a quantitative imaging of the real fetal bovine serum (FBS). This study is the first example to show that the CTZ indicators specify HSA and BSA with different colors. This study contributes to the expansion of the toolbox of optical indicators, which efficiently assays serum proteins in physiological samples. Considering that these CTZ indicators immediately report quantitative optical signals with high specificity, they provide solutions to conventional technical hurdles on point-of-care assays of serum albumins.

The laboratory investigation of pleural fluids: An update based on the available evidence

Selecting appropriate laboratory tests based on available evidence is central to improve clinical effectiveness and impacting on patient outcome. Although long studied, there is no mutual agreement upon pleural fluid (PF) management in the laboratory context. Given the experienced confusion about the real contribution of laboratory investigations to guide clinical interpretation, in this update, we tried to identify useful tests for the PF analysis, aiming to unravel critical points and to define a common line in requesting modalities and practical management. We performed a careful literature review and a deepened study on available guidelines to finalize an evidence-based test selection, intended for clinicians' use to streamline PF management. The following tests depicted the basic PF profile routinely needed: (1) abbreviated Light's criteria (PF/serum total protein ratio and PF/serum lactate dehydrogenase ratio) and (2) cell count with differential analysis of haematological cells. This profile fulfils the primary goal to determine the PF nature and discriminate between exudative and transudative effusions. In specific circumstances, clinicians may consider additional tests as follows: the albumin serum to PF gradient, which reduces exudate misclassification rate by Light's criteria in patients with cardiac failure assuming diuretics; PF triglycerides, in differentiating chylothorax from pseudochylothorax; PF glucose, for identification of parapneumonic effusions and other causes of effusion, such as rheumatoid arthritis and malignancy; PF pH, in suspected infectious pleuritis and to give indications for pleural drainage; and PF adenosine deaminase, for a rapid detection of tuberculous effusion.

Definition and application of performance specifications for measurement uncertainty of 23 common laboratory tests: linking theory to daily practice

Laboratories should estimate and validate [using analytical performance specifications (APS)] the measurement uncertainty (MU) of performed tests. It is therefore essential to appropriately define APS for MU, but also to provide a perspective on suitability of the practical application of these APS. In this study, 23 commonly ordered measurands were allocated to the models defined during the 2014 EFLM Strategic Conference to derive APS for MU. Then, we checked if the performance of commercial measuring systems used in our laboratory may achieve them. Most measurands (serum alkaline phosphatase, aspartate aminotransferase, creatine kinase, γ-glutamyltransferase, lactate dehydrogenase, pancreatic amylase, total proteins, immunoglobulin G, A, M, magnesium, urate, and prostate-specific antigen, plasma homocysteine, and blood red and white cells) were allocated to the biological variation (BV) model and desirable APS were defined accordingly (2.65%, 4.75%, 7.25%, 4.45%, 2.60%, 3.15%, 1.30%, 2.20%, 2.50%, 2.95%, 1.44%, 4.16%, 3.40%, 3.52%, 1.55%, and 5.65%, respectively). Desirable APS for serum total cholesterol (3.00%) and urine albumin (9.00%) were derived using outcome-based model. Lacking outcome-based information, serum albumin, high-density lipoprotein cholesterol, triglycerides, and blood platelets were temporarily reallocated to BV model, the corresponding desirable APS being 1.25%, 2.84%, 9.90%, and 4.85%, respectively. A mix between the two previous models was employed for serum digoxin, with a 6.00% desirable APS. In daily practice by using our laboratory systems, 16 tests fulfilled desirable and five minimum APS, while two (serum albumin and plasma homocysteine) exceeded goals, needing improvements.

Dietary yeast culture alleviates intestinal-hepatic damage related to TLR2-MyD88-NF-κB signaling pathway and antioxidant capability in Pseudobagrus ussuriensis

Yeast culture (YC), as a member of probiotics family is a natural product produced from yeast fermentation, affects of improving immunity. However, the intestine and liver injury and immunosuppression mechanism caused by SBA in fish are unclear and more functions of YC supplement in the diet need to be developed. Soybean agglutinin (SBA) is an anti-nutritional factor in soybean and leads to growth-inhibitory effect in feeding of the high proportion of soybean meal replacing fish meal (FM). Therefore, one hundred and thirty-five Pseudobagrus ussuriensis (6.5 ± 0.27 g) were randomly selected and divided into three groups (Control, SBA and YC+SBA groups). For the model, fish were fed with 2% YC for 8 weeks and then given intragastric administration of 0.2-mL SBA solution for 20 days. The results showed that SBA damaged the immune and antioxidant capacity, causing an inflammatory reaction, leading to abnormal expression of cytokines in the intestine and liver of Pseudobagrus ussuriensis. YC could effectively attenuate intestinal and liver damage and downregulate the TLR2/MyD88/NF-κB signaling pathway and suppress oxidative stress in Pseudobagrus ussuriensis. Besides, YC had obvious immune advantage, which could improve the immune ability. In summary, these results showed that YC could reduce immunosuppression and intestinal-liver injury by inhibiting the TLR2/MyD88/NF-κB signal pathway and oxidative stress induced by SBA. This study provided some explanations for the problems of fish diet caused by anti-nutritional factors from soybean meal and provided a theoretical basis for the function development of YC in aquaculture.

The Prognostic Properties of Thyroid Disorders, Hypothyroidism, and Hyperthyroidism in Predicting COVID-19 Poor Outcomes: A Systematic Review and Diagnostic Meta-analysis

Purpose

The relationship between thyroid metabolism and coronavirus disease 2019 (COVID-19) inflammation has been extensively investigated. This meta-analysis aimed to evaluate the prognostic properties of unspecified thyroid disorders, hypothyroidism and hyperthyroidism for predicting poor COVID-19 outcomes.

Methods

We conducted systematic literature searching through multiple databases-PubMed, EBSCO and CENTRAL up until 27 September 2021. The main exposure was unspecified thyroid disorders, hypothyroidism or hypothyroidism on-admission status. The outcome of interest was the COVID-19 composite poor outcome that comprises severity, mortality, ICU admission and hospitalisation.

Results

There were 24517 patients from 20 studies. Meta-analysis showed that thyroid disorder, regardless of its type, was associated with COVID-19 poor outcome (OR 2.92 (95% CI 2.09 - 4.08), P < 0.001; I2 = 71%, P < 0.001). Unspecified thyroid disorder has a sensitivity of 0.17 (0.08-0.33), specificity of 0.94 (0.88-0.97) and Area Under Curve (AUC) of 0.66. Hypothyroidism has a sensitivity of 0.24 (0.12-0.42), specificity of 0.92 (0.87-0.96) and AUC of 0.77. Hyperthyroidism has a sensitivity of 0.05 (0.02-0.11), specificity of 0.98 (0.88-1.00) and AUC of 0.36. In this pooled analysis, the posttest probability of unspecified thyroid disease, hypothyroidism and hyperthyroidism were 42%, 27% and 8% for poor outcomes, respectively.

Conclusion

Thyroid disorders are associated with poor COVID-19 prognosis.

Risk factors for early complications following arthroplasty in elderly patients with a femoral neck fracture

BACKGROUND

Early complications after arthroplasty for geriatric femoral neck fractures are known to negatively affect postoperative recovery and increase postoperative mortality. Identifying risk factors associated with early complications after arthroplasty may offer an opportunity to address and prevent these complications in many patients.

OBJECTIVE

To evaluate preoperative risk factors for early complications after arthroplasty in elderly patients with a femoral neck fracture.

METHODS

119 elderly patients with femoral neck fractures who had been treated with arthroplasty (hemiarthroplasty or total hip arthroplasty) between December 2015 and December 2018 were retrospectively analysed. Early complications were defined as any complications that did not exist preoperatively, and occurred during hospital stay after arthroplasty Preoperative clinical, epidemiological and laboratory data were collected. Binary univariable and multivariable logistic regression analysis were applied to identify predictors of early complications after arthroplasty for geriatric femoral neck fractures.

RESULTS

Median age of all patients was 80.0 (IQR 74.0-84.0) years. We identified 28 (23.5%) early complications after arthroplasty. Univariable logistic regression analysis found that preoperative body mass index (BMI p= 0.031), C-reactive protein (CRP p= 0.017) and serum Albumin (p= 0.006) were potential risk factors for early complications. Then preoperative BMI, CRP and serum Albumin were stratified and used for multivariable logistic regression analysis The multivariate logistic regression analysis showed that preoperative higher BMI (⩾ 28 kg/m2; OR 10.440; 95% CI 2.674-41.170; p= 0.001) and lower serum Albumin (⩽ 35 g/L; OR 3.933; 95% CI 1.509-10.800; p= 0.006) were independent risk factors for early complications after arthroplasty in geriatric femoral neck fractures. However, preoperative higher CRP levels (> 10 mg/L; OR 1.139; 95% CI 1034-1428; p= 0.833) was found to be not an independent risk factor for early complications.

CONCLUSION

Our results demonstrate that obesity and hypoalbuminemia are independent predictors for early complications during hospital stay after arthroplasty, which should be meticulously noted to minimize these risk factors in geriatric femoral neck fractures.

Supplementation of serum albumin is associated with improved pulmonary function: NHANES 2013–2014

Background: The serum albumin level is reflective of the function of multiple organs, such as the liver and kidneys. However, the association between serum albumin and pulmonary function is unclear; therefore, this study aimed to determine the relationship between pulmonary function and serum albumin, including the threshold of serum albumin at the changes of the pulmonary function in the total population and in different strata of population.

Methods: In this cross-sectional study, We examined the relationship between serum albumin and two independent indicators of pulmonary function: forced vital capacity (FVC) and forced expiratory volume in one second (FEV 1), using data from National Health and Nutrition Examination Survey (NHANES 2013–2014) (n = 3286). We used univariate analysis, stratified analysis, and multiple regression equation analysis to examine the correlation between serum albumin levels and FVC and FEV 1, and performed smoothed curve fitting, threshold effect, and saturation effect analysis (for stratification) to determine the threshold serum albumin level at which FVC and FEV 1 begin to change.

Results: The adjusted smoothed curve fit plot showed a linear relationship between serum albu-min levels and FVC: for every 1 g/dl increase in the serum albumin level, FVC increased by 80.40 ml (11.18, 149.61). Serum albumin and FEV 1 showed a non-linear relationship. When serum al-bumin reached the inflection point (3.8 g/dl), FEV 1 increased with increasing serum albumin and the correlation coefficient β was 205.55 (140.15, 270.95).

Conclusion: Serum albumin is a core indicator of liver function, and abnormal liver function has a direct impact on pulmonary function. In the total population, serum albumin levels were linearly and positively correlated with FVC. Above 3.6 g/dl, serum albumin was positively correlated with FEV 1. Based on the total population and different population strata, this study revealed a positive association between the serum albumin level and pulmonary function, and identified the threshold of serum albumin when Indicators of pulmonary function tests starts to rise, providing a new early warning indicator for people at high risk of pulmonary insufficiency and has positive implications for the prevention of combined respiratory failure in patients with liver insufficiency.

The relationship between hematocrit and serum albumin levels difference and mortality in elderly sepsis patients in intensive care units-a retrospective study based on two large database

BACKGROUND

Sepsis still threatens the lives of more than 300 million patients annually and elderly patients with sepsis usually have a more complicated condition and a worse prognosis. Existing studies have shown that both Hematocrit (HCT) and albumin (ALB) can be used as potential predictors of sepsis, and their difference HCT-ALB has a significant capacity to diagnose infectious diseases. Currently, there is no relevant research on the relationship between HCT-ALB and the prognosis of elderly sepsis patients. Therefore, this study aims to explore the association between HCT-ALB and mortality in elderly patients with sepsis.

METHODS

This study was a multi-center retrospective study based on the Medical Information Mart for Intensive Care (MIMIC-IV) database and the eICU Collaborative Research Database (eICU-CRD) in elderly patients with sepsis. The optimal HCT-ALB cut-off point for ICU mortality was calculated by the Youden Index based on the eICU-CRD dataset, and multivariate logistic regressions were conducted to explore the association between HCT-ALB and ICU/hospital mortality in the two databases. Subgroup analyses were performed for different parameters and comorbidity status.

RESULTS

The number of 16,127 and 3043 elderly sepsis patients were selected from two large intensive care databases (eICU-CRD and MIMIC-IV, respectively) in this study. Depending on the optimal cut-off point, patients in both eICU-CRD and MIMIC-IV were independently divided into low HCT-ALB (< 6.7) and high HCT-ALB (≥ 6.7) groups. The odds ratio (95%confidence interval) [OR (95CI%)] of the high HCT-ALB group were 1.50 (1.36,1.65) and 1.71 (1.58,1.87) for ICU and hospital mortality in the eICU-CRD database after multivariable adjustment. Similar trends in the ICU and hospital mortality [OR (95%CI) 1.41 (1.15,1.72) and 1.27 (1.07,1.51)] were observed in MIMIC-IV database. Subgroup analysis showed an interaction effect with SOFA score in the eICU-CRD database however not in MIMIC-IV dataset.

CONCLUSIONS

High HCT-ALB (≥ 6.7) is associated with 1.41 and 1.27 times ICU and hospital mortality risk in elderly patients with sepsis. HCT-ALB is simple and easy to obtain and is a promising clinical predictor of early risk stratification for elderly sepsis patients in ICU.

The prognostic values of thyroid disorders in predicting COVID-19 composite poor outcomes: A systematic review and meta-analysis

BACKGROUND AND AIMS

In this meta-analysis, we aimed to evaluate the prognostic properties of thyroid disorder during admission on poor prognosis and factors that may influence the relationship in patients with COVID-19.

METHODS

A systematic literature search of PubMed, EBSCO, and CENTRAL was conducted from inception to August 27, 2021. The main exposure was unspecified and specified thyroid disorders-hypothyroidism or hypothyroidism. The outcome of interest was the COVID-19 composite poor outcome that comprises of severity, mortality, ICU admission, and hospitalization.

RESULTS

There were 24,734 patients from 20 studies. Meta-analysis showed that thyroid disorder was associated with composite poor outcome (OR 2.87 (95% CI 2.04-4.04), p < 0.001; I² = 62.4%, p < 0.001). Meta regression showed that age (p = 0.047) and hypertension (p = 0.01), but not gender (p = 0.15), DM (p = 0.10), CAD/CVD (p = 0.38), obesity (p = 0.84), and COPD (p = 0.07) affected the association. Subgroup analysis showed that thyroid disorder increased risk of severe COVID-19 (OR 5.13 (95% CI 3.22-8.17), p < 0.05; I² = 0%, p = 0.70) and mortality (OR 2.78 (95%CI 1.31-5.90), p < 0.05; I² = 80%, p < 0.01). Pooled diagnostic analysis of thyroid disorder yielded a sensitivity of 0.22 (0.13-0.35), specificity of 0.92 (0.87-0.95), and AUC of 0.72. The probability of poor outcome was 38% in patients with thyroid disorder and 15% in patients without thyroid abnormality.

CONCLUSION

On-admission thyroid disorder was associated with poor prognosis in COVID-19 patients.

ZnO Transducers for Photoluminescence-Based Biosensors: A Review

Zinc oxide (ZnO) is a wide bandgap semiconductor material that has been widely explored for countless applications, including in biosensing. Among its interesting properties, its remarkable photoluminescence (PL), which typically exhibits an intense signal at room temperature (RT), arises as an extremely appealing alternative transduction approach due to the high sensitivity of its surface properties, providing high sensitivity and selectivity to the sensors relying on luminescence output. Therefore, even though not widely explored, in recent years some studies have been devoted to the use of the PL features of ZnO as an optical transducer for detection and quantification of specific analytes. Hence, in the present paper, we revised the works that have been published in the last few years concerning the use of ZnO nanostructures as the transducer element in different types of PL-based biosensors, namely enzymatic and immunosensors, towards the detection of analytes relevant for health and environment, like antibiotics, glucose, bacteria, virus or even tumor biomarkers. A comprehensive discussion on the possible physical mechanisms that rule the optical sensing response is also provided, as well as a warning regarding the effect that the buffer solution may play on the sensing experiments, as it was seen that the use of phosphate-containing solutions significantly affects the stability of the ZnO nanostructures, which may conduct to misleading interpretations of the sensing results and unreliable conclusions.

Prognostic properties of hypoalbuminemia in COVID-19 patients: A systematic review and diagnostic meta-analysis

BACKGROUND

Coronavirus disease 2019 (COVID-19) elicits robust inflammatory reaction that may result in a declining albumin serum level. This meta-analysis aimed to evaluate the prognostic properties of hypoalbuminemia for poor prognosis and factors that may influence the relationship.

METHOD

A systematic literature search of PubMed was conducted from inception to April 22, 2021. The main exposure was albumin level below normal range-defined by the included studies. The outcome of interest was composite poor outcome that comprises of mortality, severity, and the requirement of mechanical ventilation or intensive care unit.

RESULTS

There were 6200 patients from 19 studies. Meta-analysis showed that hypoalbuminemia was associated with composite poor outcome (OR 6.97 (95% CI 4.20-11.55), p < 0.001; I2 = 91.3%, p < 0.001). Meta-regression analysis showed that age (p = 0.44), gender (p = 0.76), HT (p = 0.97), DM (p = 0.40), CKD (p = 0.65), liver disease (p = 0.72), and malignancy (p = 0.84) did not affect the association. Subgroup analysis showed that hypoalbuminemia increased mortality (OR 6.26 (95% CI 3.26-12.04), p < 0.001; I2 = 69.6%, p < 0.01) and severity of the disease (OR 7.32 (95%CI 3.94-13.59), p < 0.001; I2 = 92.5%, p < 0.01). Pooled diagnostic analysis of hypoalbuminemia yielded a sensitivity of 0.63 (95% CI 0.52-0.72), specificity of 0.81 (95% CI 0.73-0.87), and AUC of 0.77. The probability of poor outcome was 70% in patients with hypoalbuminemia and 24% in patients with normal albumin level.

CONCLUSION

Hypoalbuminemia was associated with poor prognosis in COVID-19 patients.

PSMA: a game changer in the diagnosis and treatment of advanced prostate cancer

Although management of advanced prostate cancer is evolving, a lot of work remains to be done for patients who have exhausted all options. Molecular targeting of prostate specific membrane antigen (PSMA) is valuable not only for diagnostic but also for therapeutic reasons. PSMA is thus considered to be useful in a theranostic approach. PSMA scans are upcoming diagnostic modalities which detect metastatic lesions that are missed by conventional imaging modalities. PSMA ligand therapy is also an upcoming treatment modality that has been proven to be beneficial with minimal toxicity in patients with advanced prostate cancer that have progressed on prior therapy. In this review article, we summarize the current knowledge regarding PSMA diagnostics and PSMA ligand therapies and discuss their implication in the treatment of advanced prostate cancer.

Serum albumin concentrations are associated with disease severity and outcomes in coronavirus 19 disease (COVID-19): a systematic review and meta-analysis

Coronavirus disease 2019 (COVID-19), an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is responsible for the most threatening pandemic in modern history. The aim of this systematic review and meta-analysis was to investigate the associations between serum albumin concentrations and COVID-19 disease severity and adverse outcomes. A systematic literature search was conducted in PubMed, from inception to October 30, 2020. Sixty-seven studies in 19,760 COVID-19 patients (6141 with severe disease or poor outcome) were selected for analysis. Pooled results showed that serum albumin concentrations were significantly lower in patients with severe disease or poor outcome (standard mean difference, SMD: - 0.99 g/L; 95% CI, - 1.11 to - 0.88, p < 0.001). In multivariate meta-regression analysis, age (t =  - 2.13, p = 0.043), publication geographic area (t = 2.16, p = 0.040), white blood cell count (t =  - 2.77, p = 0.008) and C-reactive protein (t =  - 2.43, p = 0.019) were significant contributors of between-study variance. Therefore, lower serum albumin concentrations are significantly associated with disease severity and adverse outcomes in COVID-19 patients. The assessment of serum albumin concentrations might assist with early risk stratification and selection of appropriate care pathways in this group.

A Comprehensive Appraisal of Laboratory Biochemistry Tests as Major Predictors of COVID-19 Severity

CONTEXT.—

A relevant portion of coronavirus disease 2019 (COVID-19) patients develop severe disease with negative outcomes. Several biomarkers have been proposed to predict COVID-19 severity, but no definite interpretative criteria have been established to date for stratifying risk.

OBJECTIVE.—

To evaluate 6 serum biomarkers (C-reactive protein, lactate dehydrogenase, D-dimer, albumin, ferritin, and cardiac troponin T) for predicting COVID-19 severity and to define related cutoffs able to aid clinicians in risk stratification of hospitalized patients.

DESIGN.—

A retrospective study of 427 COVID-19 patients was performed. Patients were divided into groups based on their clinical outcome: nonsurvivors versus survivors and patients admitted to an intensive care unit versus others. Receiver operating characteristic curves and likelihood ratios were employed to define predictive cutoffs for evaluated markers.

RESULTS.—

Marker concentrations at peak were significantly different between groups for both selected outcomes. At univariate logistic regression analysis, all parameters were significantly associated with higher odds of death and intensive care. At the multivariate analysis, high concentrations of lactate dehydrogenase and low concentrations of albumin in serum remained significantly associated with higher odds of death, whereas only low lactate dehydrogenase activities remained associated with lower odds of intensive care admission. The best cutoffs for death prediction were greater than 731 U/L for lactate dehydrogenase and 18 g/L or lower for albumin, whereas a lactate dehydrogenase activity lower than 425 U/L was associated with a negative likelihood ratio of 0.10 for intensive treatment.

CONCLUSIONS.—

Our study identifies which biochemistry tests represent major predictors of COVID-19 severity and defines the best cutoffs for their use.

Albumin and calcium reference interval using healthy individuals and a data-mining approach

BACKGROUND

Harmonization of reference intervals for analytes that have a sound calibration and metrological traceability is a widely recommended practice. The UK Pathology Harmony has recently harmonized reference intervals for calcium and albumin. In this study, we have determined the reference intervals for calcium and albumin on the UK's most commonly used analytical platforms.

METHOD

A prospective reference population of healthy individuals was recruited according to the IFCC CRIDL criteria. A second indirect population was collected from 14 primary care setting and measured in laboratories using various analytical platforms and methods (Roche, Abbott, Beckman and Siemens analytical platforms).

RESULTS

In total, 299 subjects were recruited; the central 95th centile values for calcium for three out of four analytical platforms were in a close agreement with UK Pathology Harmony reference intervals of 2.2-2.6 mmol/L. Reference intervals of BCG methods from both cohorts and irrespective of analytical platforms were higher for both lower and upper reference limits than those for BCP. In comparison, the indirect study showed an age-related variation. The younger population reference intervals varied by up to 5.7% at the lower reference limit and up to 12% at the upper reference limit compared with Pathology Harmony reference intervals, and the older population showed a variation of up to 14% at both limits.

CONCLUSION

While calcium reference intervals can be a subject for harmonization, albumin reference intervals studied showed large variation which is unsupportive of embracing a common reference interval for albumin.

The impact of the analytical performance specifications of calcium and albumin on adjusted calcium

Aim

The generation of accurate, comparable results from traceable measurement procedures is a primary goal in harmonization efforts. In this study, the analytical performance of routine methods for calcium and albumin measurement is assessed to define the impact of the analytical bias of calcium and albumin on adjusted calcium equation performance and on reference intervals.

Method

In collaboration with the Wales External Quality Assurance Scheme, six months’ worth of anonymized data that cover a concentration range of clinical interest were collected. The data were grouped by analytical platforms/methods.

Results

Albumin BCG methods are positively biased (8%) to BCP methods. The overall bias for BCP methods ranges from 5.1 to –4.3% and the overall bias for BCG methods is from 2 to –6.7%. Bias for both methods is higher than the allowable minimal bias for albumin. Calcium concentrations for Roche Cobas CPC and NM-BAPTA, Beckman Arsenazo III, Abbott Architect Arsenazo III were within bias of 1.5 to –1%. However, Siemens calcium methods CPC and Arsenazo III appear to suffer from concentration-dependent bias ranging from +3 to –6%, which exceeds even the minimal allowable limits for calcium (1.3%). Adjusted calcium shows significant bias of 11%. Even with the exclusion of Siemens Advia, the scatter of adjusted calcium results exceeds that for total calcium.

Conclusion

This study shows wider than acceptable analytical variation for albumin and calcium. This variation may contribute to overall adjusted calcium equations variation and invalidate the application of a harmonized reference interval for calcium and albumin.

Stratifying Brain Tumour Histological Sub-Types: The Application of ATR-FTIR Serum Spectroscopy in Secondary Care

Patients living with brain tumours have the highest average years of life lost of any cancer, ultimately reducing average life expectancy by 20 years. Diagnosis depends on brain imaging and most often confirmatory tissue biopsy for histology. The majority of patients experience non-specific symptoms, such as headache, and may be reviewed in primary care on multiple occasions before diagnosis is made. Sixty-two per cent of patients are diagnosed on brain imaging performed when they deteriorate and present to the emergency department. Histological diagnosis from invasive surgical biopsy is necessary prior to definitive treatment, because imaging techniques alone have difficulty in distinguishing between several types of brain cancer. However, surgery itself does not necessarily control tumour growth, and risks morbidity for the patient. Due to their similar features on brain scans, glioblastoma, primary central nervous system lymphoma and brain metastases have been known to cause radiological confusion. Non-invasive tests that support stratification of tumour subtype would enhance early personalisation of treatment selection and reduce the delay and risks associated with surgery for many patients. Techniques involving vibrational spectroscopy, such as attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, have previously demonstrated analytical capabilities for cancer diagnostics. In this study, infrared spectra from 641 blood serum samples obtained from brain cancer and control patients have been collected. Firstly, we highlight the capability of ATR-FTIR to distinguish between healthy controls and brain cancer at sensitivities and specificities above 90%, before defining subtle differences in protein secondary structures between patient groups through Amide I deconvolution. We successfully differentiate several types of brain lesions (glioblastoma, meningioma, primary central nervous system lymphoma and metastasis) with balanced accuracies >80%. A reliable blood serum test capable of stratifying brain tumours in secondary care could potentially avoid surgery and speed up the time to definitive therapy, which would be of great value for both neurologists and patients.

Prognostic Value of Pre-Treatment Prognostic Nutritional Index in Esophageal Cancer: A Systematic Review and Meta-Analysis

Background: Prognostic nutritional index (PNI), combining albumin and lymphocyte counts, which represent the nutritional and immune status, was considered as an effective predictor for the patient's prognosis after surgery. To comprehensively analyze the relative effectiveness of prognostic performance of pretreatment PNI in esophageal cancer (EC), we performed this meta-analysis. Methods: We performed a systematic search in PubMed, Embase, CNKI, and Web of Science. The hazard ratios (HRs) or odds ratios (ORs) with their corresponding 95% confidence intervals (CIs) were extracted to explore the correlation between PNI and the post-operative survival of patients with EC, including overall survival (OS), recurrence-free survival (RFS), and post-operative complications. The Newcastle-Ottawa Scale (NOS) was applied to estimate the quality of the included studies. The Begg's test was applied to assess the publication bias. Results: A total of 13 articles with 3,543 patients, were included in our meta-analysis, and nine studies reported OS in 2,731 EC patients. The pooled results of the nine studies suggested that EC patients with a low PNI would have a worse overall survival (HR = 1.14, 95% CI 0.99-1.31, p < 0.05). The integrated results also indicated that the PNI was a negative predictor for RFS. Conclusion: This meta-analysis indicated a high correlation between PNI and post-operative survival of EC. EC patients with low PNI values tend to have worse OS and may be at a higher risk of EC recurrence. However, more relevant researches are needed to confirm the association between PNI and post-operative complications of EC.

The effect of different analytical platforms and methods on the performance of population-specific adjusted calcium equation

Background

A recent attempt to improve the diagnostic value of adjusted calcium addressed a primary care-specific adjusted calcium equation, but validated the new equation for Roche Cobas, BCG and NM-BAPTA methods only. In this study, we aim to validate a population-specific equation for other methods and platforms.

Method

We collected retrospective patient data-sets from 15 hospital laboratories using a range of commercially available analytical platforms and methods for calcium and albumin measurements. Raw data-sets were collected and filtered according to Payne’s criteria, and separate adjusted calcium equations were derived for hospitalized and primary care patients.

Results

Mean albumin and calcium results were significantly higher in primary care populations ( P <  0.0001). The prevalence of hypocalcaemia using adjusted calcium ranged between 6% and 44% for inpatient data-sets and was higher in users of BCG methods. The application of community-specific adjustment equation to primary care data-sets reduced the prevalence of hypocalcaemia (mean 1.7%, range 0.8–3.7%).

Conclusion

We demonstrated that the use of a community-specific calcium adjustment equation to a primary care population reduces both the percentage and the variation of hypocalcaemia between different laboratories.

Application of Fisetin to the Quantitation of Serum Albumin

Fisetin (3,3′,4′,7-tetrahydroxyflavone) is a widely distributed natural flavonol. It interacts with albumin, and thereby generates a fluorescence signal quantitatively. Based on such optical characteristics, we postulated that fisetin was applicable to the quantitation of albumin as an indicator. To establish the fisetin-based albumin assay, we examined the optical properties of fisetin and fisetin–albumin complex. The assay conditions were fine-tuned to fit for the actual concentration of serum albumin and to generate an optimal signal with a high signal-to-background ratio. The reaction between fisetin and albumin was linear in a wide range of concentrations. Non-protein serum components did not interfere with the reaction. The reactivity of fisetin was apparently specific for albumin among serum proteins. Both plasma and serum were compatible with the assay. The samples could be stored in a refrigerator or a freezer without the loss of reactivity toward fisetin. The generation and decay rates of the signal were acceptable for manual handling. The recovery of fortified albumin in serum was confirmed and the assay was validated with human sera. Fisetin-based albumin assay is suitable for clinical laboratory testing, considering the simple and short procedure, high specificity and sensitivity, linearity over a wide range of albumin concentrations, and, presumably, potential automatability.

Bias between two methods of albumin measurement in the white rhinoceros, Ceratotherium simum

BACKGROUND

The bromocresol green (BCG) method has been reported to overestimate serum albumin concentration in several species due to non-specific binding to globulins. As the white rhinoceros has high concentrations of serum globulins, significant differences in albumin measured by the BCG method, and the field method of agarose gel serum protein electrophoresis (SPE) are expected.

OBJECTIVES

We aimed to compare the BCG and SPE methods for albumin determination in the serum of white rhinoceroses.

METHODS

SPE and BCG albumin were measured in 82 white rhinoceros serum samples. Results were compared using Bland-Altman difference plots and Passing-Bablok regression analysis.

RESULTS

BCG albumin showed a significant mean constant positive bias of 7 g/L, or 36%, which was more than the total allowable error of 15% and was clinically significant. Methods were not comparable within the inherent imprecision of each method.

CONCLUSIONS

The BCG method overestimated albumin concentrations in this species compared with agarose gel SPE, and method-specific reference intervals should be used.

The Future of PSMA-Targeted Radionuclide Therapy: An Overview of Recent Preclinical Research

Prostate specific membrane antigen (PSMA) has become a major focus point in the research and development of prostate cancer (PCa) imaging and therapeutic strategies using radiolabeled tracers. PSMA has shown to be an excellent target for PCa theranostics because of its high expression on the membrane of PCa cells and the increase in expression during disease progression. Therefore, numerous PSMA-targeting tracers have been developed and (pre)clinically studied with promising results. However, many of these PSMA-targeting tracers show uptake in healthy organs such as the salivary glands, causing radiotoxicity. Furthermore, not all patients respond to PSMA-targeted radionuclide therapy (TRT). This created the necessity of additional preclinical research studies in which existing tracers are reevaluated and new tracers are developed in order to improve PSMA-TRT by protecting the (PSMA-expressing) healthy organs and improving tumor uptake. In this review we will give an overview of the recent preclinical research projects regarding PCa-TRT using PSMA-specific radiotracers, which will give an indication of where the PSMA-TRT research movement is going and what we can expect in future clinical trials.

Harmonization in laboratory medicine: more than clinical chemistry?

The goal of harmonizing laboratory information is to contribute to quality in patient care, ultimately improving upon patient outcomes and safety. The main focus of harmonization and standardization initiatives has been on analytical processes within the laboratory walls, clinical chemistry tests in particular. However, two major evidences obtained in recent years show that harmonization should be promoted not only in the analytical phase but also in all steps of the testing process, encompassing the entire field of laboratory medicine, including innovative areas (e.g. “omics”) rather than just conventional clinical chemistry tests. A large body of evidence demonstrates the vulnerability of the extra-analytical phases of the testing cycle. Because only “good biological samples” can assure good analytical quality, a closer interconnection between the different phases of the cycle is needed. In order to provide reliable and accurate laboratory information, harmonization activities should cover all steps of the cycle from the “pre-pre-analytical” phase (right choice of test at right time for right patient) through the analytical steps (right results with right report) to the “post-post-analytical” steps (right and timely acknowledgment of laboratory information, right interpretation and utilization with any necessary advice as to what to do next with the information provided). In addition, modern clinical laboratories are performing a broad menu of hundreds of tests, covering both traditional and innovative subspecialties of the discipline. In addition, according to a centered viewpoint, harmonization initiatives should not be addressed exclusively to clinical chemistry tests but should also include all areas of laboratory medicine.

Defining permissible limits for the combined uncertainty budget in the implementation of metrological traceability

In addition to the correct implementation of calibration traceability, the definition and the achievement of an appropriate analytical performance specification for the total uncertainty budget (G_U) is essential to ensure that laboratory measurements are clinically usable. To understand if it is possible to fulfil these specifications, limits for combined uncertainty across the entire metrological traceability chain should be defined. We recommended that no more than one third of G_U should be consumed by the uncertainty of higher order references and ≤50% of G_U by the combined measurement uncertainty at the manufacturer's calibration level. The remaining allowable uncertainty should be available for random sources, i.e. for the imprecision of the commercial measuring system (including the reagent batch-to-batch variation) and the individual laboratory performance, as a safety margin to fulfil G_U. Based on this approach, it is of interest to assess for each analyte measured in the clinical laboratory the status of the uncertainty budget of its measurement associated with the selected metrological traceability chain. Accordingly, we report three didactic cases that could occur in the clinical practice. This approach is very helpful to identify those analytes for which further technological improvements are probably needed to reduce uncertainty associated with their measurement.

Measurement uncertainty: Friend or foe?

The definition and enforcement of a reference measurement system, based on the implementation of metrological traceability of patients' results to higher order reference methods and materials, together with a clinically acceptable level of measurement uncertainty, are fundamental requirements to produce accurate and equivalent laboratory results. The uncertainty associated with each step of the traceability chain should be governed to obtain a final combined uncertainty on clinical samples fulfilling the requested performance specifications. It is important that end-users (i.e., clinical laboratory) may know and verify how in vitro diagnostics (IVD) manufacturers have implemented the traceability of their calibrators and estimated the corresponding uncertainty. However, full information about traceability and combined uncertainty of calibrators is currently very difficult to obtain. Laboratory professionals should investigate the need to reduce the uncertainty of the higher order metrological references and/or to increase the precision of commercial measuring systems. Accordingly, the measurement uncertainty should not be considered a parameter to be calculated by clinical laboratories just to fulfil the accreditation standards, but it must become a key quality indicator to describe both the performance of an IVD measuring system and the laboratory itself.

The prognostic value of C-reactive protein/albumin ratio in human malignancies: an updated meta-analysis

Purpose

This study aims to investigate the prognostic value of pretreatment C-reactive protein/albumin ratio (CAR) in human malignancies by an updated meta-analysis.

Methods

PubMed, Web of Science, Cochrane Library and Wanfang databases were searched. Pooled hazard ratios (HRs) and odds ratios (ORs) with their corresponding 95% confidence intervals (CIs) were used as effective values.

Results

A total of 25 studies with 12,097 patients were included in this meta-analysis. Pooled results showed that high pretreatment CAR was associated with poor overall survival (OS) (HR =1.99, 95% CI: 1.65–2.40, P=0.000) and poor disease-free survival (HR =1.55, 95% CI: 1.34–1.79, P=0.000). In addition, high pretreatment CAR was associated with increased 5-year mortality (OR =2.74, 95% CI: 2.11–3.55, P=0.000). Moreover, subgroup analysis demonstrated that high CAR was associated with poor OS despite variations in publication year, country, sample size, CAR cut-off value and treatment. However, high CAR was associated with poor OS in human malignancies except colorectal cancer (HR =1.64, 95% CI: 0.96–2.80, P=0.069).

Conclusion

High pretreatment CAR indicates poor prognosis in human malignancies except colorectal cancer. Thus, pretreatment CAR serves as a prognostic marker in human malignancies and could be used in the evaluation of prognosis in clinical work.

State of Harmonization of 24 Serum Albumin Measurement Procedures and Implications for Medical Decisions

BACKGROUND

Measurements of serum and plasma albumin are widely used in medicine, including as indicators of quality of patient care in renal dialysis centers.

METHODS

Pools were prepared from residual patient serum (n = 50) and heparin plasma (n = 48) from patients without renal disease, and serum from patients with kidney failure before hemodialysis (n = 53). Albumin was measured in all samples and in ERM-DA470k/IFCC reference material (RM) by 3 immunochemical, 9 bromcresol green (BCG), and 12 bromcresol purple (BCP) methods.

RESULTS

Two of 3 immunochemical procedures, 5 of 9 BCG, and 10 of 12 BCP methods recovered the RM value within its uncertainty. One immunochemical and 3 BCG methods were biased vs the RM value. Random error components were small for all measurement procedures. The Tina-quant immunochemical method was chosen as the reference measurement procedure based on recovery and results of error analyses. Mean biases for BCG vs Tina-quant were 1.5% to 13.9% and were larger at lower albumin concentrations. BCP methods' mean biases were −5.4% to 1.2% irrespective of albumin concentration. Biases for plasma samples were generally higher than for serum samples for all method types. For most measurement procedures, biases were lower for serum from patients on hemodialysis vs patients without kidney disease.

CONCLUSIONS

Significant differences among immunochemical, BCG, and BCP methods compromise interpretation of serum albumin results. Guidelines and calculations for clinical management of kidney and other diseases must consider the method used for albumin measurement until harmonization can be achieved.

Serum albumin and muscle measures in a cohort of healthy young and old participants

Consensus on clinically valid diagnostic criteria for sarcopenia requires a systematical assessment of the association of its candidate measures of muscle mass, muscle strength, and physical performance on one side and muscle-related clinical parameters on the other side. In this study, we systematically assessed associations between serum albumin as a muscle-related parameter and muscle measures in 172 healthy young (aged 18-30 years) and 271 old participants (aged 69-81 year) from the European MYOAGE study. Muscle measures included relative muscle mass, i.e., total- and appendicular lean mass (ALM) percentage, absolute muscle mass, i.e., ALM/height(2) and total lean mass in kilograms, handgrip strength, and walking speed. Muscle measures were standardized and analyzed in multivariate linear regression models, stratified by age. Adjustment models included age, body composition, C-reactive protein and lifestyle factors. In young participants, serum albumin was positively associated with lean mass percentage (p = 0.007) and with ALM percentage (p = 0.001). In old participants, serum albumin was not associated with any of the muscle measures. In conclusion, the association between serum albumin and muscle measures was only found in healthy young participants and the strongest for measures of relative muscle mass.

Role and Responsibilities of Laboratory Medicine Specialists in the Verification OF Metrological Traceability of in vitro Medical Diagnostics

To be accurate and equivalent, laboratory results should be traceable to higher-order references. Furthermore, their quality should fulfill acceptable measurement uncertainty as defined to fit the intended clinical use. With this aim, in vitro diagnostics (IVD) manufacturers should define a calibration hierarchy to assign traceable values to their system calibrators and to fulfill during this process uncertainty limits for calibrators, which should represent a proportion of the uncertainty budget allowed for clinical laboratory results. It is therefore important that, on one hand, the laboratory profession clearly defines the clinically acceptable uncertainty for relevant tests and, on the other hand, end-users may know and verify how manufacturers have implemented the traceability of their calibrators and estimated the corresponding uncertainty. Important tools for IVD traceability surveillance are quality control programmes through the daily verification by clinical laboratories that control materials of analytical systems are in the manufacturer’s declared validation range [Internal Quality Control (IQC) component I] and the organization of External Quality Assessment Schemes meeting metrological criteria. In a separate way, clinical laboratories should also monitor the reliability of employed commercial systems through the IQC component II, devoted to estimation of the measurement uncertainty due to random effects, which includes analytical system imprecision together with individual laboratory performance in terms of variability.

Age and sex variation in serum albumin concentration: an observational study

BACKGROUND

In the UK, a common reference interval for serum albumin is widely used irrespective of age or sex. Implicit in this is that laboratories produce analytically similar results. This paper challenges the validity of this approach.

METHODS

A three-week collection of results sent to all primary care centres in England has been analysed by age, sex and laboratory. In all, 1,079,193 serum albumin reports were included in this analysis.

RESULTS

The mean population serum albumin concentration increases to peak at around age 20 years and then decreases with increasing age. Values in females decrease more rapidly but become close to male values at 60 years. The variation between laboratories was large and potentially clinically significant.

CONCLUSIONS

Reference intervals for serum albumin should be stratified by age and sex. Until there is greater methodological standardization, laboratories should determine their own reference intervals and not accept a single consensus reference interval.

Verification of in vitro medical diagnostics (IVD) metrological traceability: responsibilities and strategies

To be accurate and equivalent, laboratory results should be traceable to higher-order references. Furthermore, their analytical performance should fulfill acceptable measurement uncertainty criteria defined to fit the intended clinical use. With this aim, In Vitro Diagnostics (IVD) manufacturers should define a calibration hierarchy to assign traceable values to their system calibrators and to fulfill during this process uncertainty limits for calibrators, which should represent a proportion of the uncertainty budget allowed for laboratory results. It is important that end-users may know and verify how manufacturers have implemented the traceability of their calibrators and estimated the corresponding uncertainty. However, full information about traceability and combined uncertainty of calibrators is currently not available. Important tools for IVD traceability surveillance are the verification by laboratories of the consistency of declared performance during daily operations performed in accordance with the manufacturer's instructions and the organization of appropriately structured External Quality Assessment (EQA) programs. The former activity should be accomplished by analyzing system control materials and confirming that current measurements are in the manufacturer's established control range. With regard to EQA, it is mandatory that target values for materials are assigned with reference procedures by accredited laboratories, that materials are commutable and that a clinically allowable inaccuracy for participant's results is defined.