[Differential diagnosis of anemia]

Anemia is often encountered in clinical practice. It has to be noted that anemia is only a symptom of an underlying disease. Early, correct and consequent diagnosis is crucial in order to prevent late detection of fatal disease or to prescribe contraindicated therapy. The combined use of a morphologic and physiologic classification allows for understanding and correct classification of anemia in a specific patient. In this respect, the determination of reticulocyte counts is of special importance. Further targeted biochemical, morphological and immunological analysis leads to the definitive diagnosis of anemia. A large proportion of the anemias can be diagnosed and treated by the general practitioner. However, involvement of a haematologist is recommended in several clinical situations, such as newly diagnosed haemolytic anemia, as well as in patients with complex, equivocal or therapy-refractory anemia or certain normocytic hyporegenerative anemias. This paper presents a differentiated stepwise approach in diagnosing anemic disorders.

[Conventional and new laboratory parameters in the evaluation of hematologic disease]

Laboratory investigation plays a crucial role in the workup of hematological disease. The well established method of morphological analysis of blood components has been continuously complemented by other methods. On one hand, these consist of considerable improvements of methods employed for automated cell enumeration allowing for early and accurate detection of cell subpopulations, and quantification of valuable red cell parameters, which are of use in the differential diagnosis of anemia. On the other hand, several parameters for the differentiation of microcytic anemia have become available often allowing for the sometimes difficult diagnosis of anemia of chronic disease, iron deficiency anemia, or thalassemia (ferritin, soluble transferrin receptor, transferrin saturation, RDW, zinc protoporphyrin, as well as reticulocyte indices CHr, Ret-Y Hypo%). In macrocytic anemia, introduction of methods to measure methylmalonic acid (MMA), homocystein, holotranscobalamin (holo-TC), complement the determinations of vitamin concentrations (vitamin B12, folic acid in serum and erythrocytes). Employing these newer parameters in addition to the well established ones allows for detection of early or combined disease. The clinician has to know the diagnostic characteristics not only of the old but also of the newer parameters.

Diagnostic Characteristics of 3-Parameter and 2-Parameter Equations for the Calculation of a Combined Indicator of Vitamin B12 Status to Predict Cobalamin Deficiency in a Large Mixed Patient Population

BACKGROUND

A combined indicator for the determination of vitamin B12 status (4cB12) that employs four markers of vitamin B12 status (i.e., holotranscobalamin, HoloTC; vitamin B12, B12; methyl malonic acid, MMA; and homocysteine, Hcy) has been proposed for the comprehensive assessment of B12 status. We aimed to compare recently published 2- (2cB12) and 3-parameter (3cB12) cB12 equations missing one or two markers of B12 status with the established four-parameter cB12 (4cB12).

METHODS

In 3,614 routine samples in which HoloTC, B12, MMA, Hcy and serum folate were measured, cB12 was assessed with 4cB12, as well as with four 3cB12 and six 2cB12 equations. Diagnostic accuracy (AUC) curves were calculated by receiver operating characteristic (ROC) curve analysis with the four-parameter equation (4cB12) as an index. Furthermore, we investigated whether calculating cB12 in addition to a 2-step algorithm employing the same parameters would add diagnostic value for the diagnosis of vitamin B12 deficiency.

RESULTS

HoloTC showed the highest diagnostic accuracy among the single markers (AUC = 0.94). The cB12 equation using HoloTC and MMA (2cB12HoloTC/MMA) had the highest AUC among the 2-parameter equations (0.98). Among the 3-parameter equations, 3cB12HoloTC/MMA/Hcy and 3cB12HoloTC/B12/MMA revealed an AUC of 0.99, which was significantly higher than that of 2cB12HoloTC/MMA (p < 0.01). Calculating 2cB12HoloTC/MMA in addition to using a stepwise algorithm employing HoloTC and MMA for diagnosis of vitamin B12 deficiency increased the positive likelihood ratio from 12.1 to 42.6.

CONCLUSIONS

cB12 calculated with two or three markers of B12 status provides a good approximation of the 4cB12 equation. A 2cB12 equation employing the same parameters improved diagnostic accuracy compared to the use of a 2-step diagnostic algorithm alone. Our results suggest, that laboratories should consider enriching their reports by additionally reporting a corresponding 2cB12 or 3cB12 to results obtained in stepwise diagnostic algorithms.

Changes of coagulation parameters during high altitude expedition

PRINCIPLES

Data on changes of haemostatic parameters at altitudes above 5000 m are very limited. So far it is unknown, whether altered coagulation could contribute to the development of acute mountain sickness.

METHODS

Thirty four healthy mountaineers were randomised to two acclimatisation protocols and undertook an expedition on Muztagh Ata (7549 m) in China. Tests were performed at five altitudes up to 6865 m. Haemostatic parameters, such as PT, aPTT, D-Dimer, APC-Resistance (APCR), von Willebrand Factor activity (RCo), ADAMTS-13 & C-Natriuretic Peptide (CNP) were assessed together with Lake Louise AMS score.

RESULTS

D-Dimer significantly increased with increasing altitude (median 0.62 to 0.81 mcg/L, p <0.0001). During ascent, PT increased (83% to >100%) and APCR decreased significantly from 0.95 to 0.8 (p <0.01). Furthermore, a significant increase of aPTT (38 to 43 sec) was paralleled by significant changes of RCo (102% to 62%) (both p <0.001). There were no significant changes in ADAMTS-13 and CNP. No significant relationship between investigated parameters and AMS scores could be detected. When comparing the participants of the two acclimatisation protocols, there was an overall higher RCo in patients with a faster ascent protocol (p = 0.04). This was accompanied by lower ADAMTS-13 of the coagulation system in these patients (p = 0.04).

CONCLUSIONS

Coagulation parameters change significantly during hypobaric hypoxia. Whereas we could detect no association between AMS scores and coagulation parameters, our results do show some parameters to be associated with an acclimatisation protocol and a successful ascent to the summit.

Elementary Laboratory Assays as Biomarkers of Ageing: Support for Treatment of COVID-19?

Youth, working age and the elderly: On a timeline, chronological age (CA) and biological age (BA) may dissociate; nosological entities manifest themselves at different BAs. In determining which disease corresponds to a given age decade, statistical registries of causes of death are unreliable and this does not change with SARS CoV-2 infection. Beyond adolescence, ageing metrics involve estimations of changes in fitness, including prediction models to estimate the number of remaining years left to live. A substantial disparity in biomarker levels and health status of ageing can be observed: the difference in CA and BA in the large cohorts under consideration is glaring. Here, we focus more closely on ageing and senescence metrics in order to make information available for risk analysis non the least with COVID-19, including the most recent risk factors of ABO blood type and 3p21.31 chromosome cluster impacting on C5a and SC5b-9 plasma levels. From the multitude of routine medical laboratory assays, a potentially meaningful set of assays aimed to best reflect the stage of individual senescence; hence risk factors the observational prospective SENIORLABOR study of 1,467 healthy elderly performed since 2009 and similar approaches since 1958 can be instantiated as a network to combine a set of elementary laboratory assays quantifying senescence.

How much should we sequence? An analysis of the Swiss SARS-CoV-2 surveillance effort

During the SARS-CoV-2 pandemic, many countries directed substantial resources toward genomic surveillance to detect and track viral variants. There is a debate over how much sequencing effort is necessary in national surveillance programs for SARS-CoV-2 and future pandemic threats. We aimed to investigate the effect of reduced sequencing on surveillance outcomes in a large genomic data set from Switzerland, comprising more than 143k sequences. We employed a uniform downsampling strategy using 100 iterations each to investigate the effects of fewer available sequences on the surveillance outcomes: (i) first detection of variants of concern (VOCs), (ii) speed of introduction of VOCs, (iii) diversity of lineages, (iv) first cluster detection of VOCs, (v) density of active clusters, and (vi) geographic spread of clusters. The impact of downsampling on VOC detection is disparate for the three VOC lineages, but many outcomes including introduction and cluster detection could be recapitulated even with only 35% of the original sequencing effort. The effect on the observed speed of introduction and first detection of clusters was more sensitive to reduced sequencing effort for some VOCs, in particular Omicron and Delta, respectively. A genomic surveillance program needs a balance between societal benefits and costs. While the overall national dynamics of the pandemic could be recapitulated by a reduced sequencing effort, the effect is strongly lineage-dependent-something that is unknown at the time of sequencing-and comes at the cost of accuracy, in particular for tracking the emergence of potential VOCs.IMPORTANCESwitzerland had one of the most comprehensive genomic surveillance systems during the COVID-19 pandemic. Such programs need to strike a balance between societal benefits and program costs. Our study aims to answer the question: How would surveillance outcomes have changed had we sequenced less? We find that some outcomes but also certain viral lineages are more affected than others by sequencing less. However, sequencing to around a third of the original effort still captured many important outcomes for the variants of concern such as their first detection but affected more strongly other measures like the detection of first transmission clusters for some lineages. Our work highlights the importance of setting predefined targets for a national genomic surveillance program based on which sequencing effort should be determined. Additionally, the use of a centralized surveillance platform facilitates aggregating data on a national level for rapid public health responses as well as post-analyses.

Design and Validation of a Sensitive Multisteroid LC-MS/MS Assay for the Routine Clinical Use: One-Step Sample Preparation with Phospholipid Removal and Comparison to Immunoassays

Steroid analysis in clinical laboratories is dominated by immunoassays (IAs) that have a high sample turnover but are inherently limited in trueness, precision, and sensitivity. Liquid chromatography coupled to mass spectrometry (LC-MS/MS) has proved to be a far more capable tool, delivering better sensitivity, specificity, and the possibility of parallel analysis of multiple steroids and metabolites, providing the endocrinologist with more reliable and comprehensive diagnostic information. An LC-MS/MS assay with gradient elution over less than eight minutes and a one-step sample preparation combining protein precipitation with phospholipid removal of off-line solid-phase extraction was developed and validated. It allowed the quantification of 11-deoxycorticosterone (11-DOC), 11-deoxycortisol (11-DF), 17-OH-progesterone (17P), 21-deoxycortisol (21-DF), androstenedione (ANDRO), aldosterone (ALDO), corticosterone (CC), cortisol (CL), cortisone (CN), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), dihydrotestosterone (DHT), estradiol (E2), progesterone (PROG), and testosterone (TES) in human serum. Interday imprecision was generally better than 15%, trueness was proven by recovery experiments with ISO 17034-certified reference materials, proficiency testing (UK NEQAS), and measuring serum reference standards. In-house comparison against IVD-CE-certified immunoassays (IA) for 17P, ANDRO, CL, DHEAS, E2, PROG, and TES was conducted by assessing leftover routine patient samples and purpose-built patient serum pools. None of the compared routine IAs were meeting the standards of the LC-MS/MS. Insufficient overall comparability was found for ANDRO and 17P (mean bias > +65%). Accuracy limitations at lower concentrations were present in IAs for PROG, E2, and TES.

An isotope dilution-liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS)-based candidate reference measurement procedure for the quantification of zonisamide in human serum and plasma

OBJECTIVES

To describe and validate an isotope dilution-liquid chromatograph-tandem mass spectrometry (ID-LC-MS/MS) based reference measurement procedure (RMP) for zonisamide to accurately measure serum and plasma concentrations.

METHODS

Quantitative nuclear magnetic resonance (qNMR) spectroscopy was employed to determine the absolute content of the reference material used in order to establish traceability to SI units. Separation of zonisamide from known or unknown interferences was performed on a C8 column. For sample preparation a protocol based on protein precipitation in combination with a high dilution step was established. Assay validation and determination of measurement uncertainty were performed based on guidelines from the Clinical and Laboratory Standards Institute, the International Conference on Harmonization, and the Guide to the expression of uncertainty in measurement.

RESULTS

The RMP was proven to be highly selective and specific with no evidence of a matrix effect, allowing for quantification of zonisamide within the range of 1.50-60.0 μg/mL. Intermediate precision was <1.4 % and repeatability CV ranged from 0.7 to 1.2 % over all concentration levels. The relative mean bias ranged from 0.0 to 0.8 % for native serum levels and from 0.2 to 2.0 % for Li-heparin plasma levels. The measurement uncertainties for single measurements and target value assignment ranged from 1.1 to 1.4 % and 0.8-1.0 %, respectively.

CONCLUSIONS

We present a novel LC-MS/MS-based candidate RMP for zonisamide in human serum and plasma which provides a traceable and reliable platform for the standardization of routine assays and evaluation of clinically relevant samples.

Selected topics of the 4th International Cooperative Study Group meeting on immune thrombocytopenia revisited

The Intercontinental Cooperative immune thrombocytopenia (ITP) Study Group (ICIS) held its 4th Expert Meeting in September 2012 in Montreux, Switzerland. The program reunited researchers and clinicians from all over the globe and was organized with lectures and seminars for real-time exchange of latest information. Platelets target victims of autoimmune disease on their own, participating under physiological conditions in the immune network; these small cells are more immunologically savvy than previously thought. Currently, researchers focus their attention on regulatory T and regulatory B cells, ie, cells that might have a decisive impact on how ITP spontaneously resolves or evolves into chronic disease. Diagnostic criteria and prognosis are increasingly benefiting from molecular biological tests, and therapy has evolved with the availability of biosimilar agents and recombinant hormones or blockers of their receptors.

Genetic architecture of spatial electrical biomarkers for cardiac arrhythmia and relationship with cardiovascular disease

The 3-dimensional spatial and 2-dimensional frontal QRS-T angles are measures derived from the vectorcardiogram. They are independent risk predictors for arrhythmia, but the underlying biology is unknown. Using multi-ancestry genome-wide association studies we identify 61 (58 previously unreported) loci for the spatial QRS-T angle (N = 118,780) and 11 for the frontal QRS-T angle (N = 159,715). Seven out of the 61 spatial QRS-T angle loci have not been reported for other electrocardiographic measures. Enrichments are observed in pathways related to cardiac and vascular development, muscle contraction, and hypertrophy. Pairwise genome-wide association studies with classical ECG traits identify shared genetic influences with PR interval and QRS duration. Phenome-wide scanning indicate associations with atrial fibrillation, atrioventricular block and arterial embolism and genetically determined QRS-T angle measures are associated with fascicular and bundle branch block (and also atrioventricular block for the frontal QRS-T angle). We identify potential biology involved in the QRS-T angle and their genetic relationships with cardiovascular traits and diseases, may inform future research and risk prediction.

Genome-wide analysis in over 1 million individuals of European ancestry yields improved polygenic risk scores for blood pressure traits

Hypertension affects more than one billion people worldwide. Here we identify 113 novel loci, reporting a total of 2,103 independent genetic signals (P < 5 × 10-8) from the largest single-stage blood pressure (BP) genome-wide association study to date (n = 1,028,980 European individuals). These associations explain more than 60% of single nucleotide polymorphism-based BP heritability. Comparing top versus bottom deciles of polygenic risk scores (PRSs) reveals clinically meaningful differences in BP (16.9 mmHg systolic BP, 95% CI, 15.5-18.2 mmHg, P = 2.22 × 10-126) and more than a sevenfold higher odds of hypertension risk (odds ratio, 7.33; 95% CI, 5.54-9.70; P = 4.13 × 10-44) in an independent dataset. Adding PRS into hypertension-prediction models increased the area under the receiver operating characteristic curve (AUROC) from 0.791 (95% CI, 0.781-0.801) to 0.826 (95% CI, 0.817-0.836, ∆AUROC, 0.035, P = 1.98 × 10-34). We compare the 2,103 loci results in non-European ancestries and show significant PRS associations in a large African-American sample. Secondary analyses implicate 500 genes previously unreported for BP. Our study highlights the role of increasingly large genomic studies for precision health research.

Laboruntersuchungen in der Gesundheitsvorsorge

Vorsorge hat zum Ziel, dass Personen gesünder älter werden. Vorsorgeuntersuchungen sollen Krankheiten an der Entstehung hindern oder sie früh erkennen, damit rechtzeitig interveniert werden kann. Für die Anforderungen an Vorsorgeuntersuchungen existieren Kriterien. Neben Anamnese und körperlicher Untersuchung kommen im Rahmen von Vorsorgeprogrammen auch Labortests zur Anwendung. Dazu gehören die Bestimmung von Blutglucose, Lipiden sowie der Testung von okkultem Blut im Stuhl. Weitere Parameter (TSH, PSA, Kreatinin, Albumin/Kreatinin Ratio) kommen in speziellen Situationen in Betracht. Zurzeit existiert für diese letztgenannten Tests noch keine solide Indikation für einen breiten Einsatz im Rahmen eines Massenscreenings. Der vorliegende Artikel stellt die Rolle von Labortests im Rahmen von Vorsorgeuntersuchungen vor und beleuchtet insbesondere auch Empfehlungen zu deren Einsatz in der Schweiz und in Österreich.

Phosphorylated tau in Alzheimer's disease

There is a need for blood biomarkers to detect individuals at different Alzheimer's disease (AD) stages because obtaining cerebrospinal fluid-based biomarkers is invasive and costly. Plasma phosphorylated tau proteins (p-tau) have shown potential as such biomarkers. This systematic review was conducted according to the PRISMA guidelines and aimed to determine whether quantification of plasma tau phosphorylated at threonine 181 (p-tau181), threonine 217 (p-tau217) and threonine 231 (p-tau231) is informative in the diagnosis of AD. All p-tau isoforms increase as a function of Aβ-accumulation and discriminate healthy individuals from those at preclinical AD stages with high accuracy. P-tau231 increases earliest, followed by p-tau181 and p-tau217. In advanced stages, all p-tau isoforms are associated with the clinical classification of AD and increase with disease severity, with the greatest increase seen for p-tau217. This is also reflected by a better correlation of p-tau217 with Aβ scans, whereas both, p-tau217 and p-tau181 correlated equally with tau scans. However, at the very advanced stages, p-tau181 begins to plateau, which may mirror the trajectory of the Aβ pathology and indicate an association with a more intermediate risk of AD. Across the AD continuum, the incremental increase in all biomarkers is associated with structural changes in widespread brain regions and underlying cognitive decline. Furthermore, all isoforms differentiate AD from non-AD neurodegenerative disorders, making them specific for AD. Incorporating p-tau181, p-tau217 and p-tau231 in clinical use requires further studies to examine ideal cut-points and harmonize assays.

Burden of post-acute COVID-19 sequelae in healthcare workers and its course over a 30-month period-results from a prospective multicentre cohort

PURPOSE

As healthcare workers (HCW) have been disproportionally affected by COVID-19, its post-acute sequelae (PASC) in HCW can impact healthcare systems. We assessed the burden and course of PASC in HCW over a 30-month period.

METHODS

In a prospective multicentre HCW cohort in Switzerland, PASC surveys were conducted in 03/2021, 09/2021, 06/2022, 04/2023, and 10/2023. Stratified by viral variant at first infection, the prevalence of PASC symptoms, self-experienced PASC and the Post-COVID Functional Status (PCFS) were analysed cross-sectionally in 10/2023, self-perceived success of therapeutic measures used was assessed. The evolution of PASC symptoms and PCFS in Wild-type and non-Wild-type infected HCW compared to uninfected controls was analysed longitudinally across all surveys.

RESULTS

In cross-sectional analysis, 1704 HCW (median age 47 years, 82.2% female) were included. Thereof, 30.7% reported ≥ 1 PASC symptom in 10/2023, with 115 (6.7%) stating to have or have had PASC. Both were most common after Wild-type infection compared to other variants. Overall, 17/115 (15%) indicated relevant/severe restrictions in their daily activities and of 85 (74%) that tried ≥ 1 measure against their symptoms, 69 (81%) reported having benefitted. Longitudinal analysis (n = 653) showed a significantly higher proportion of Wild-type infected HCW to report PASC symptoms compared to controls in 03/2021 (+ 21%, 95% CI 4-39), with decreasing trend (+ 7%, 95%CI -10-25 in 10/2023). This effect was not evident for non-Wild-type infected HCW.

CONCLUSIONS

Over a 30 month period, overall PASC burden in our HCW cohort decreased, although 1% still experience relevant restrictions in their daily life; Wild-type infected individuals show the highest disease burden.

A Large-Scale Genome-Wide Study of Gene-Sleep Duration Interactions for Blood Pressure in 811,405 Individuals from Diverse Populations

Although both short and long sleep duration are associated with elevated hypertension risk, our understanding of their interplay with biological pathways governing blood pressure remains limited. To address this, we carried out genome-wide cross-population gene-by-short-sleep and long-sleep duration interaction analyses for three blood pressure traits (systolic, diastolic, and pulse pressure) in 811,405 individuals from diverse population groups. We discover 22 novel gene-sleep duration interaction loci for blood pressure, mapped to 23 genes. Investigating these genes' functional implications shed light on neurological, thyroidal, bone metabolism, and hematopoietic pathways that necessitate future investigation for blood pressure management that caters to sleep health lifestyle. Non-overlap between short sleep (12) and long sleep (10) interactions underscores the plausible nature of distinct influences of both sleep duration extremes in cardiovascular health. Several of our loci are specific towards a particular population background or sex, emphasizing the importance of addressing heterogeneity entangled in gene-environment interactions, when considering precision medicine design approaches for blood pressure management.

SARS-CoV-2 Vaccination is Not Associated With Involuntary Childlessness in Female Healthcare Workers: A Multicenter Cohort Study

BACKGROUND

There is debate about the causes of the recent birth rate decline in high-income countries worldwide. During the pandemic, concern about the effects on reproductive health has caused vaccine hesitancy. We investigated the association of SARS-CoV-2 vaccination and infection with involuntary childlessness.

METHODS

Females in fertility age within a prospective multicenter cohort of healthcare workers (HCW) were followed since August 2020. Data on baseline health, SARS-CoV-2-infection, and vaccination were obtained and regularly updated, in which serum samples were collected repetitively and screened for anti-nucleocapsid and anti-spike antibodies. In October 2023, participants indicated the presence of involuntary childlessness with onset during the pandemic, whereas those indicating an onset before the pandemic were excluded. The association of involuntary childlessness and SARS-CoV-2-vaccination and infection was investigated using univariable and multivariable analysis. Sensitivity analysis was performed to compare those reporting involuntary childlessness with those birthing a child since 2020.

RESULTS

Of 798 participants, 26 (3.2%) reported involuntary childlessness starting since the pandemic. Of the involuntary childless women, 73.1% (19/26) were vaccinated compared to 86.0% (664/772) without involuntary childlessness (p = 0.73). SARS-CoV-2 infection was reported by 76.9% (20/26) compared to 72.4% (559/772) of controls (p = 0.64). Neither SARS-CoV-2 vaccination (aOR 0.91 per dose, 95%CI 0.67-1.26) nor infection (aOR per infection 1.05, 95%CI 0.62-1.71) was associated with involuntary childlessness. Sensitivity analysis confirmed these results.

CONCLUSIONS

Among female HCW of fertility age, 3.2% indicated involuntary childlessness, which is comparable to pre-pandemic data. No association between involuntary childlessness and SARS-CoV-2 vaccination or infection was found.

A Large-Scale Genome-wide Association Study of Blood Pressure Accounting for Gene-Depressive Symptomatology Interactions in 564,680 Individuals from Diverse Populations

Background Gene-environment interactions may enhance our understanding of hypertension. Our previous study highlighted the importance of considering psychosocial factors in gene discovery for blood pressure (BP) but was limited in statistical power and population diversity. To address these challenges, we conducted a multi-population genome-wide association study (GWAS) of BP accounting for gene-depressive symptomatology (DEPR) interactions in a larger and more diverse sample. Results Our study included 564,680 adults aged 18 years or older from 67 cohorts and 4 population backgrounds (African (5%), Asian (7%), European (85%), and Hispanic (3%)). We discovered seven novel gene-DEPR interaction loci for BP traits. These loci mapped to genes implicated in neurogenesis ( TGFA , CASP3 ), lipid metabolism ( ACSL1 ), neuronal apoptosis ( CASP3 ), and synaptic activity ( CNTN6 , DBI ). We also identified evidence for gene-DEPR interaction at nine known BP loci, further suggesting links between mood disturbance and BP regulation. Of the 16 identified loci, 11 loci were derived from African, Asian, or Hispanic populations. Post-GWAS analyses prioritized 36 genes, including genes involved in synaptic functions ( DOCK4 , MAGI2 ) and neuronal signaling ( CCK , UGDH , SLC01A2 ). Integrative druggability analyses identified 11 druggable candidate gene targets, including genes implicated in pathways linked to mood disorders as well as gene products targeted by known antihypertensive drugs. Conclusions Our findings emphasize the importance of considering gene-DEPR interactions on BP, particularly in non-European populations. Our prioritized genes and druggable targets highlight biological pathways connecting mood disorders and hypertension and suggest opportunities for BP drug repurposing and risk factor prevention, especially in individuals with DEPR.