Biological Variation Estimates for Plasma Copeptin and Clinical Implications.

Background: Plasma copeptin measurement is useful for the differential diagnoses of polyuria-polydipsia syndrome. It has also been proposed as a prognostic marker for cardiovascular diseases. However, limited information is available about the within- (CVI) and between-subject (CVG) biological variation (BV).

Spectral and temporal detection of blood bilirubin level using a point-of-care device.

Bilirubin is a biomarker for liver inflammation used to assess liver functions. Its concentration in the blood has been measured using a range of techniques both in clinical and point-of-care settings. Existing point-of-care devices utilize a spectral approach, namely dual-wavelength absorption measurement, to assess the blood bilirubin concentration.

A review of clinical guidelines, laboratory recommendations and external quality assurance programs for monoclonal gammopathy testing.

Monoclonal gammopathy (MG) is a spectrum of diseases ranging from the benign asymptomatic monoclonal gammopathy of undetermined significance to the malignant multiple myeloma. Clinical guidelines and laboratory recommendations have been developed to inform best practices in the diagnosis, monitoring, and management of MG. In this review, the pathophysiology, relevant laboratory testing recommended in clinical practice guidelines and laboratory recommendations related to MG testing and reporting are examined.

Screening for and diagnosis of monoclonal gammopathy.

Monoclonal gammopathy is a spectrum of disorders characterised by clonal proliferation of plasma cells or lymphocytes, which produce abnormal immunoglobulin or its components (monoclonal proteins). Monoclonal gammopathies are often categorised as low-tumour-burden diseases (eg, amyloid light chain (AL) amyloidosis), premalignant disorders (such as monoclonal gammopathy of undetermined significance and smouldering multiple myeloma), and malignancies (eg, multiple myeloma and Waldenström's macroglobulinaemia). Such diversity of concentration and structure makes monoclonal protein a challenging clonal marker.

Uncertainty in measurement and the renal tubular reabsorption of phosphate.

Objectives: The ratio of tubular maximum reabsorption of phosphate to glomerular filtration rate (TmP/GFR) is used to evaluate renal phosphate transport. TmP/GFR is most probably calculated using the formula described by Kenny and Glen or obtained from the nomogram described by Walton and Bijvoet. Even though the calculation itself is well described, no attention has been given to its measurement uncertainty (MU).

Between and within calibration variation: implications for internal quality control rules.

The variability between calibrations can be larger than the within calibration variation for some measurement procedures, that is a large CV:CV ratio. In this study, we examined the false rejection rate and probability of bias detection of quality control (QC) rules at varying calibration CV:CV ratios. Historical QC data for six representative routine clinical chemistry serum measurement procedures (calcium, creatinine, aspartate aminotransferase, thyrotrophin, prostate specific antigen and gentamicin) were extracted to derive the CV:CV ratios using analysis of variance.

SARS-CoV-2 Testing Strategies in the Diagnosis and Management of COVID-19 Patients in Low-Income Countries: A Scoping Review.

The accuracy of diagnostic laboratory tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can impact downstream clinical procedures in managing and controlling the outbreak of coronavirus disease 2019 (COVID-19). To assess the effectiveness of laboratory tools for managing COVID-19 patients in low-income countries (LICs), we systematically searched the PubMed, Embase, Scopus and CINHAL databases for reports published between January 2020 and June 2022. We found that 22 of 1303 articles reported the performance of various SARS-CoV-2 detection tools across 10 LICs.

Impaired Fibrinolytic Potential Predicts Oxygen Requirement in COVID-19.

Abnormal coagulation and fibrinolysis contributes to the respiratory distress syndrome in COVID-19. We aimed to explore the association of impaired fibrinolytic potential with disease severity and oxygen requirement in hospitalized patients. Adults admitted to hospital with confirmed COVID-19 infection between 1-31 January 2022 were included, corresponding to the first Omicron outbreak in Melbourne, Victoria.

Aldosterone, Renin, and Aldosterone-to-Renin Ratio Variability in Screening for Primary Aldosteronism.

Context: The plasma aldosterone concentration (PAC), renin, and aldosterone-to-renin ratio (ARR) are used to screen for primary aldosteronism (PA). Substantial intra-individual variability of PAC and ARR using plasma renin activity in the context of usual antihypertensive therapy has been described, but there is no data on ARR variability calculated using direct renin concentration (DRC).

Objective: To describe the intra-individual variability of PAC, DRC, and ARR in the absence of interfering medications in patients with and without PA.

Plasma Angiotensin Converting Enzyme 2 (ACE2) Activity in Healthy Controls and Patients with Cardiovascular Risk Factors and/or Disease.

Angiotensin converting enzyme 2 (ACE2) is an endogenous negative regulator of the renin-angiotensin system, a key factor in the development of cardiovascular disease (CVD). ACE2 is also used by SARS-CoV-2 for host cell entry. Given that COVID-19 is associated with hypercoagulability, it is timely to explore the potential relationship between plasma ACE2 activity and the coagulation profile.

Laboratory markers of severity across three COVID-19 outbreaks in Australia: has Omicron and vaccinations changed disease presentation?

COVID-19 has rapidly evolved since it was first discovered in December 2019. We aimed to retrospectively review our experience with COVID-19 infection across 2020-2022, focusing on differences in laboratory markers at presentation. Consecutive adult patients admitted to hospital with confirmed COVID-19 infection were retrospectively reviewed across three periods (29/3/2020-29/9/2020, 16/8/2021-13/10/2021 and 1/1/2022-31/1/2022), correlating with the lineages B.

Performance of the aldosterone-to-renin ratio as a screening test for primary aldosteronism in primary care.

Primary aldosteronism (PA) is the most common and potentially curable form of secondary hypertension, affecting 5-10% of primary care patients with hypertension. Primary care physicians have an important role in initiating the screening for PA in patients with hypertension and referring to a specialist service depending on the screening test results. The currently recommended screening test for PA is the plasma aldosterone-to-renin ratio (ARR).

Risk factors and early prediction of clinical deterioration and mortality in adult COVID-19 inpatients: an Australian tertiary hospital experience.

Background: Early recognition of severe COVID-19 is essential for timely patient triage.

Aims: To report clinical and laboratory findings and patient outcomes at a tertiary hospital in Melbourne, Australia.

Methods: This is a retrospective study of adult inpatients with COVID-19 admitted to Northern Health from March to September 2020.