Inferring causal direction between two traits using R2 with application to transcriptome-wide association studies.

In Mendelian randomization, two single SNP-trait correlation-based methods have been developed to infer the causal direction between an exposure (e.g., a gene) and an outcome (e.g., a trait), called MR Steiger's method and its recent extension called Causal Direction-Ratio (CD-Ratio). Here we propose an approach based on R2, the coefficient of determination, to combine information from multiple (possibly correlated) SNPs to simultaneously infer the presence and direction of a causal relationship between an exposure and an outcome. Our proposed method generalizes Steiger's method from using a single SNP to multiple SNPs as IVs. It is especially useful in transcriptome-wide association studies (TWASs) (and similar applications) with typically small sample sizes for gene expression (or another molecular trait) data, providing a more flexible and powerful approach to inferring causal directions. It can be applied to GWAS summary data with a reference panel. We also discuss the influence of invalid IVs and introduce a new approach called R2S to select and remove invalid IVs (if any) to enhance the robustness. We compared the performance of the proposed method with existing methods in simulations to demonstrate its advantages. We applied the methods to identify causal genes for high/low-density lipoprotein cholesterol (HDL/LDL) using the individual-level GTEx gene expression data and UK Biobank GWAS data. The proposed method was able to confirm some well-known causal genes while identifying some novel ones. Additionally, we illustrated an application of the proposed method to GWAS summary to infer causal relationships between HDL/LDL and stroke/coronary artery disease (CAD).

Multidimensional Cross-Linking and Real-Time Informatics for Multiprotein Interaction Studies.

Chemical cross-linking combined with mass spectrometry is a technique used to study protein structures and identify protein complexes. Traditionally, chemical cross-linkers contain two reactive groups, allowing them to covalently bond a pair of proximal residues, either within a protein or between two proteins. The output of a cross-linking experiment is a list of interacting site pairs that provide structural constraints for modeling of new structures and complexes. Due to the binary reactive nature of cross-linking reagents, only pairs of interacting sites can be directly observed, and assembly of higher-order structures typically requires prior knowledge of complex composition or iterative docking to produce a putative model. Here, we describe a new tetrameric cross-linker bearing four amine-reactive groups, allowing it to covalently link up to four proteins simultaneously and a real-time instrument method to facilitate the identification of these tetrameric cross-links. We applied this new cross-linker to isolated mitochondria and identified a number of higher-order cross-links in various OXPHOS complexes and ATP synthase, demonstrating its utility in characterizing complex interfaces. We also show that higher-order cross-links can be used to effectively filter models of large protein assemblies generated by using Alphafold. Higher-dimensional cross-linking provides a new avenue for characterizing multiple protein interfaces, even in complex samples such as intact mitochondria.

Inserting Pre-analytical Chromatographic Priming Runs Significantly Improves Targeted Pathway Proteomics with Sample Multiplexing.

GoDig, a platform for targeted pathway proteomics without the need for manual assay scheduling or synthetic standards, is a powerful, flexible, and easy-to-use method that uses tandem mass tags to increase sample throughput up to 18-fold relative to label-free methods. Though the protein-level success rates of GoDig are high, the peptide-level success rates are more limited, hampering assays of harder-to-quantify proteins and site-specific phenomena. To guide the optimization of GoDig assays as well as improvements to the GoDig platform, we created GoDigViewer, a new stand-alone software that provides detailed visualizations of GoDig runs. GoDigViewer guided the implementation of "priming runs," an acquisition mode with significantly higher success rates. In this mode, two or more chromatographic priming runs are automatically performed to improve the accuracy and precision of target elution orders, followed by analytical runs which quantify targets. Using priming runs, success rates exceeded 97% for a list of 400 peptide targets and 95% for a list of 200 targets that are usually not quantified using untargeted mass spectrometry. We used priming runs to establish a quantitative assay of 125 macroautophagy proteins that had a >95% success rate and revealed differences in macroautophagy expression profiles across four human cell lines.

Bias correction for inverse variance weighting Mendelian randomization.

Inverse-variance weighted two-sample Mendelian randomization (IVW-MR) is the most widely used approach that utilizes genome-wide association studies (GWAS) summary statistics to infer the existence and the strength of the causal effect between an exposure and an outcome. Estimates from this approach can be subject to different biases due to the use of weak instruments and winner's curse, which can change as a function of the overlap between the exposure and outcome samples. We developed a method (MRlap) that simultaneously considers weak instrument bias and winner's curse while accounting for potential sample overlap. Assuming spike-and-slab genomic architecture and leveraging linkage disequilibrium score regression and other techniques, we could analytically derive, reliably estimate, and hence correct for the bias of IVW-MR using association summary statistics only. We tested our approach using simulated data for a wide range of realistic settings. In all the explored scenarios, our correction reduced the bias, in some situations by as much as 30-fold. In addition, our results are consistent with the fact that the strength of the biases will decrease as the sample size increases and we also showed that the overall bias is also dependent on the genetic architecture of the exposure, and traits with low heritability and/or high polygenicity are more strongly affected. Applying MRlap to obesity-related exposures revealed statistically significant differences between IVW-based and corrected effects, both for nonoverlapping and fully overlapping samples. Our method not only reduces bias in causal effect estimation but also enables the use of much larger GWAS sample sizes, by allowing for potentially overlapping samples.

Comparison of caffeine consumption behavior with plasma caffeine levels as exposure measures in drug-target Mendelian randomization.

Mendelian randomization is an epidemiological technique that can explore the potential effect of perturbing a pharmacological target. Plasma caffeine levels can be used as a biomarker to measure the pharmacological effects of caffeine. Alternatively, this can be assessed using a behavioral proxy, such as average number of caffeinated drinks consumed per day. Either variable can be used as the exposure in a Mendelian randomization investigation, and to select which genetic variants to use as instrumental variables. Another possibility is to choose variants in gene regions with known biological relevance to caffeine level regulation. These choices affect the causal question that is being addressed by the analysis, and the validity of the analysis assumptions. Further, even when using the same genetic variants, the sign of Mendelian randomization estimates (positive or negative) can change depending on the choice of exposure. Some genetic variants that decrease caffeine metabolism associate with higher levels of plasma caffeine, but lower levels of caffeine consumption, as individuals with these variants require less caffeine consumption for the same physiological effect. We explore Mendelian randomization estimates for the effect of caffeine on body mass index, and discuss implications for variant and exposure choice in drug target Mendelian randomization investigations.

X-ray beam diagnostics at the MID instrument of the European X-ray Free-Electron Laser Facility.

The Materials Imaging and Dynamics (MID) instrument at the European X-ray Free-Electron Laser Facility (EuXFEL) is equipped with a multipurpose diagnostic end-station (DES) at the end of the instrument. The imager unit in DES is a key tool for aligning the beam to a standard trajectory and for adjusting optical elements such as focusing lenses or the split-and-delay line. Furthermore, the DES features a bent-diamond-crystal spectrometer to disperse the spectrum of the direct beam to a line detector. This enables pulse-resolved characterization of the EuXFEL spectrum to provide X-ray energy calibration, and the spectrometer is particularly useful in commissioning special modes of the accelerator. Together with diamond-based intensity monitors, the imager and spectrometer form the DES unit which also contains a heavy-duty beamstop at the end of the MID instrument. Here, we describe the setup in detail and provide exemplary beam diagnostic results.

Collision energies: Optimization strategies for bottom-up proteomics.

Mass-spectrometry coupled to liquid chromatography is an indispensable tool in the field of proteomics. In the last decades, more and more complex and diverse biochemical and biomedical questions have arisen. Problems to be solved involve protein identification, quantitative analysis, screening of low abundance modifications, handling matrix effect, and concentrations differing by orders of magnitude. This led the development of more tailored protocols and problem centered proteomics workflows, including advanced choice of experimental parameters. In the most widespread bottom-up approach, the choice of collision energy in tandem mass spectrometric experiments has outstanding role. This review presents the collision energy optimization strategies in the field of proteomics which can help fully exploit the potential of MS based proteomics techniques. A systematic collection of use case studies is then presented to serve as a starting point for related further scientific work. Finally, this article discusses the issue of comparing results from different studies or obtained on different instruments, and it gives some hints on methodology transfer between laboratories based on measurement of reference species.

A field diagnostic method for rapid and sensitive detection of mpox virus.

The mpox outbreak has subdued with fewer reported cases at the present in high-income countries. It is known that mpox virus (MPXV) infection has been epidemic for more than 50 years in African countries. The ancestral MPXV strain has changed into multiple clades, indicating the ongoing evolution of MPXV, which reflects the historical neglect of mpox in Africa, especially after smallpox eradication, and bestows the danger of more severe mpox epidemics in the future. It is thus imperative to continue the development of mpox diagnostics and treatments so we can be prepared in the event of a new mpox epidemic. In this study, we have developed an MPXV detection tool that leverages the recombinase-aid amplification assay by integrating lateral flow strips (RAA-LF) and one-step sample DNA preparation, with visible readout, no need of laboratory instrument, and ready for field deployment. The detection limit reaches 10 copies per reaction. The performance of our RAA-FL assay in diagnosing mpox clinical samples is on par with that of the quantitative polymerase chain reaction (PCR) assay. Taken together, we have developed a point-of-care RAA-LF method of high accuracy and sensitivity, readily deployable for field detection of MPXV. This diagnostic tool is expected to improve and accelerate field- and self-diagnosis, allow timely isolation and treatment, reduce the spread of MPXV, thus effectively mitigate MPXV outbreak in the future.

In Situ Measurement of Evolving Excited-State Dynamics During Deposition and Processing of Organic Films by Single-Shot Transient Absorption.

A significant advantage of organic semiconductors over many of their inorganic counterparts is solution processability. However, solution processing commonly yields heterogeneous films with properties that are highly sensitive to the conditions and parameters of casting and processing. Measuring the key properties of these materials in situ, during film production, can provide new insight into the mechanism of these processing steps and how they lead to the emergence of the final organic film properties. The excited-state dynamics is often of import in photovoltaic, electronic, and light-emitting devices. This review focuses on single-shot transient absorption, which measures a transient spectrum in a single shot, enabling the rapid measurement of unstable chemical systems such as organic films during their casting and processing. We review the principles of instrument design and provide examples of the utility of this spectroscopy for measuring organic films during their production.

Development and characterization of discontinuous atmospheric pressure interface - Dual pressure chamber miniature mass spectrometer.

Miniaturized mass spectrometers have become increasingly prevalent for real-time detection and analysis, owing to their compact size and portability. The pursuit of performance enhancement in these instruments is a pivotal objective within the domain of mass spectrometry miniaturization. This study introduces a novel miniature mass spectrometer featuring a discontinuous atmospheric pressure interface and a dual pressure chamber. Compared to conventional single-chamber, discontinuous sampling interface mass spectrometers, the newly developed instrument demonstrates a more than tenfold improvement in detection efficiency. This significant enhancement is achieved without the need for complex control of switch coupling time series, thereby streamlining the circuit design and improving the instrument's fault tolerance. Furthermore, by capitalizing on the benefits of discontinuous sampling, the instrument reduces the operational pressure relative to traditional continuous sampling in differential pressure vacuum chambers. It accommodates larger inlet capillary (0.38 mm) and skimmer (0.5 mm) diameters, leading to a ninefold increase in response strength for risperidone and lowering the detection limit to 0.5 ppb. The instrument's capacity for rapid drug detection, along with enhanced resolution and detection limits, underscores its potential utility. Additionally, it facilitates the use of smaller mechanical pumps, significantly diminishing both the instrument's volume and power consumption. This presents a promising avenue for further miniaturization of mass spectrometers.

Cerebellar-Induced Aphasia After Stroke: Evidence for the "Linguistic Cerebellum".

The cerebellum is traditionally known to subserve motor functions. However, for several decades, the concept of the "cerebellar cognitive affective syndrome" has evolved. Studies in healthy participants and patients have confirmed the cerebellar role in language. The exact involvement of the cerebellum regarding cerebellar aphasia remains uncertain. We included 43 cerebellar stroke patients who were tested at 3 months post-onset with the Boston Naming Test (BNT), the Token Test (TT), and the Diagnostic Instrument for Mild Aphasia (DIMA). Lesion side (left/right) and volume (cm3) were investigated. Patients significantly deviated on the following: BNT (p<0.001), TT (p<0.05), DIMA subtests: sentences repetition (p=0.001), semantic odd-picture-out (p<0.05), sentence completion (p<0.05) without an effect of lesion location (left/right) or volume (cm3) (p>0.05). Our clinical study confirms a non-lateralized cerebellar aphasia post-stroke, characterized by impairments in word retrieval, phonology, semantics, and syntax resembling cerebral-induced aphasia. The integral cerebellum appears to interact with eloquent cortico-subcortical language areas.

A novel approach to understanding and assessing the emotional side of type 1 diabetes: The Type 1-Diabetes Distress Assessment System.

AIMS: To describe the development of a novel, conceptually sound instrument with contemporary content for assessing diabetes distress (DD) among adults with type 1 diabetes. METHODS: Qualitative interviews with 15 adults and 7 clinicians were used to develop Core (intensity of DD emotional burden) and primary Source (key DD contributors) items. These were administered to a national sample recruited from the TCOYD Research Registry, T1D Exchange and our previous studies. Exploratory and confirmatory factor analyses were undertaken, along with reliability and construct validity studies, and cut-point analyses to determine elevated DD. RESULTS: Analyses based on 650 respondents yielded an 8-item Core DD scale (α = 0.95) and 10 2- or 3-item DD Source Scales (α range = 0.53-0.88): Financial Worries, Interpersonal Challenges, Management Difficulties, Shame, Hypoglycemia Concerns, Healthcare Quality, Lack of Diabetes Resources, Technology Challenges, Burden to Others and Worries about Complications. Core and Source scores were significantly associated with criterion variables: Higher DD scores were significantly linked with higher HbA1C, more frequent episodes of severe hypoglycaemia, missed boluses, and poorer quality of life (p > 0.001). A ≥2.0 scale cut-point to define elevated DD is suggested. CONCLUSIONS: The new T1-Diabetes Distress Assessment System demonstrated good reliability and validity, and with measures of both Core emotional burden and Sources of DD, it provides a contemporary, flexible and practical approach to assessing DD that can be used seamlessly to inform intervention for clinicians and researchers.

Clinical accuracy of instrument-based SARS-CoV-2 antigen diagnostic tests: a systematic review and meta-analysis.

BACKGROUND: During the COVID-19 pandemic, antigen diagnostic tests were frequently used for screening, triage, and diagnosis. Novel instrument-based antigen tests (iAg tests) hold the promise of outperforming their instrument-free, visually-read counterparts. Here, we provide a systematic review and meta-analysis of the SARS-CoV-2 iAg tests' clinical accuracy. METHODS: We systematically searched MEDLINE (via PubMed), Web of Science, medRxiv, and bioRxiv for articles published before November 7th, 2022, evaluating the accuracy of iAg tests for SARS-CoV-2 detection. We performed a random effects meta-analysis to estimate sensitivity and specificity and used the QUADAS-2 tool to assess study quality and risk of bias. Sub-group analysis was conducted based on Ct value range, IFU-conformity, age, symptom presence and duration, and the variant of concern. RESULTS: We screened the titles and abstracts of 20,431 articles and included 114 publications that fulfilled the inclusion criteria. Additionally, we incorporated three articles sourced from the FIND website, totaling 117 studies encompassing 95,181 individuals, which evaluated the clinical accuracy of 24 commercial COVID-19 iAg tests. The studies varied in risk of bias but showed high applicability. Of 24 iAg tests from 99 studies assessed in the meta-analysis, the pooled sensitivity and specificity compared to molecular testing of a paired NP swab sample were 76.7% (95% CI 73.5 to 79.7) and 98.4% (95% CI 98.0 to 98.7), respectively. Higher sensitivity was noted in individuals with high viral load (99.6% [95% CI 96.8 to 100] at Ct-level ≤ 20) and within the first week of symptom onset (84.6% [95% CI 78.2 to 89.3]), but did not differ between tests conducted as per manufacturer's instructions and those conducted differently, or between point-of-care and lab-based testing. CONCLUSION: Overall, iAg tests have a high pooled specificity but a moderate pooled sensitivity, according to our analysis. The pooled sensitivity increases with lower Ct-values (a proxy for viral load), or within the first week of symptom onset, enabling reliable identification of most COVID-19 cases and highlighting the importance of context in test selection. The study underscores the need for careful evaluation considering performance variations and operational features of iAg tests.

Innovating in a bioimaging core through instrument development.

Developing devices and instrumentation in a bioimaging core facility is an important part of the innovation mandate inherent in the core facility model but is a complex area due to the required skills and investments, and the impossibility of a universally applicable model. Here, we seek to define technological innovation in microscopy and situate it within the wider core facility innovation portfolio, highlighting how strategic development can accelerate access to innovative imaging modalities and increase service range, and thus maintain the cutting edge needed for sustainability. We consider technology development from the perspective of core facility staff and their stakeholders as well as their research environment and aim to present a practical guide to the 'Why, When, and How' of developing and integrating innovative technology in the core facility portfolio. Core facilities need to innovate to stay up to date. However, how to carry out the innovation is not very obvious. One area of innovation in imaging core facilities is the building of optical setups. However, the creation of optical setups requires specific skill sets, time, and investments. Consequently, the topic of whether a core facility should develop optical devices is discussed as controversial. Here, we provide resources that should help get into this topic, and we discuss different options when and how it makes sense to build optical devices in core facilities. We discuss various aspects, including consequences for staff and the relation of the core to the institute, and also broaden the scope toward other areas of innovation.

Psychometric properties of disease-specific health-related quality of life instruments for food allergy: A COnsensus-based Standards for the selection of health Measurement INstruments-based systematic review.

Food allergies severely impact the health-related quality of life (HRQoL) of patients and their caregivers (family or informal caregivers). Currently there is no comprehensive review to provide an overview and critical assessment of the instruments in the field. Six databases were searched from inception until 10 August 2023, and a combination of subject terms and free words was used to search the literature. We used the COnsensus-based Standards for the selection of health Measurement INstruments methodology (COSMIN) to evaluate the measurement properties of the instruments. Forty-one studies reported on ten eligible instruments. Based on COSMIN guidelines, one instrument was recommended for Grade A, and the remaining nine instruments were recommended for Grade B. The Grade A instrument identified, the Food Allergy Quality of Life Questionnaire-Parent Form (FAQLQ-PF), can help researchers assess the effectiveness of treatment for patients with food allergy and to understand the psychosocial impact of the disease on patients.

The female self-advocacy in Cancer Survivorship scale is a psychometrically sound measure of self-advocacy in male cancer survivors.

OBJECTIVE: To develop and psychometrically evaluate an adapted version of the Female Self-Advocacy in Cancer Survivorship (FSACS) Scale in men with a history of cancer. METHODS: This psychometric instrument development and validation study used a two-phase approach to first adapt the FSACS Scale items to reflect the experience of men with a history of cancer and then evaluate the psychometric properties of the adapted scale compared to the original FSACS Scale. The study was conducted from December 2018 through April 2022 through cancer clinics, patient registries, and national advocacy organizations. We evaluated scale reliability and validity using reliability coefficients, exploratory and confirmatory factor analyses, and item analyses to determine a final set of scale items. RESULTS: Item responses from N = 171 men with a history of cancer were evaluated to determine scale validity. After removing poor-performing items based on item-level analyses, factor analyses confirmed that a 3-factor structure of both the adapted and original FSACS Scale best fit the scale. The 10 new items did not outperform the original 20-item scale and were therefore excluded from the final scale. The final 20-item scale explained 87.94% of item variance and subscale's Cronbach α varied from 0.65 to 0.86. CONCLUSION: The SACS Scale can be used in research and clinical contexts to assess the propensity of men and women to get their needs, values, and priorities met in the face of a challenge.

The PompeQoL questionnaire: Development and validation of a new measure for children and adolescents with Pompe disease.

Genetic disorders pose great challenges for affected individuals and their families, as they must cope with the irreversible nature of the disease and a life-long dependence on medical assistance and treatment. Children and adolescents dealing with Pompe disease (PD) often struggle to keep up with their peers in physical activities. To gain valuable insights into their subjective experiences and better understand their perception and coping related to daily challenges linked to their condition and treatment, the use of standardized questionnaires is crucial. This study introduces the novel PompeQoL 1.0 questionnaire for children and adolescents with PD, designed for comprehensive assessment of both disease-specific FDH and HRQoL through self- and proxy reports. Content validity was ensured through patients' and parents' involvement at the initial stages of development and in subsequent cognitive debriefing process. Participants found the questionnaire easy to understand, answerable, relevant, and comprehensive. Adjustments based on feedback from patients and their parents improved its utility as a patient- and observer-reported outcome measure. After careful item examination, 52 items were selected, demonstrating moderate to excellent test-retest reliability for most scales and initial evidence for satisfactory construct validity. The PompeQoL questionnaire stands as a valuable screening instrument for both clinical and research purposes. Future research should prioritize additional revisions and larger validation studies, focusing on testing the questionnaire in clinical practice and trials. Nevertheless, the PompeQoL 1.0 stands out as the first standardized measure providing insights into disease-specific FDH and HRQoL among children and adolescents with various forms of PD.

Instrument and Supply Variability: An Opportunity to Reduce the Carbon Footprint of the Operating Room.

INTRODUCTION: Reducing costs and carbon footprints are important, parallel priorities for the US health-care system. Within surgery, reducing the number of instruments that are sterilized and disposable supplies that are used for each operation may help achieve both goals. We wanted to measure the existing variability in surgical instrument and supply choices and assess whether standardization could have a meaningful cost and environmental impact. METHODS: We analyzed surgeon preference cards for common general surgery operations at our hospital to measure the number of sterilizable instrument trays and supplies used by each surgeon for each operation. From this data, we calculated supply costs, carbon footprint, and median operative time and studied the variability in each of these metrics. RESULTS: Among the ten operations studied, variability in sterilizable instrument trays requested on surgeon preference cards ranged from one to eight. Variability in disposable supplies requested ranged from 17 to 45. Variability in open supply costs ranged from $104 to $4184. Variability in carbon footprint ranged from 17 to 708 kg CO2e. If the highest-cost surgeon for each operation switched their preference card to that of the median-cost surgeon, $245,343 in open supply costs and 41,708 kg CO2e could be saved. CONCLUSIONS: There is significant variability in the instrument and supply choices of surgeons performing common general surgery operations. Standardizing this variability may lead to meaningful cost savings and carbon footprint reduction, especially if scaled across the entire health system.

The Prognostic Test Accuracy of the Short and Standard Forms of the Montreal Cognitive Assessment.

INTRODUCTION: Cognitive impairment is a critical concern in stroke care, and international guidelines recommend early cognitive screening. The aim of this study was to determine the prognostic accuracy of both the short and standard forms of the Montreal Cognitive Assessment (MoCA) in predicting long-term cognitive recovery following a stroke. METHODS: For this study, we used data from the Efficacy of Fluoxetine - a Randomized Controlled Trial in Stroke (EFFECTS) study, which encompassed stroke patients from 35 Swedish centers over the period from 2014 to 2019. Cognitive assessments were initially conducted at 2-15 days post-stroke, with follow-up data gathered at 6 months. We used the MoCA for objective cognitive evaluation. For assessing subjective cognitive impairment, we used the memory and thinking domain of the Stroke Impact Scale. For psychometric evaluation of the short Swedish version of MoCA (s-MoCA-SWE), we used cross tables and binary logistic regression. RESULTS: The study included 1,141 patients (62.2% men; median [interquartile range; IQR] age, 72.3 [13.2] years; median [IQR] stroke severity, 3.0 [3.0]). At baseline, the prevalence of cognitive impairment was 71.7% according to the s-MoCA-SWE (≤12) and 67.0% according to the MoCA (≤25). The s-MoCA-SWE demonstrated a sensitivity of 92.3% for correctly identifying patients with objective cognitive impairment and 81.5% for identifying those with subjective impairments at 6 months. Although the s-MoCA-SWE had higher sensitivity, the MoCA had a more balanced sensitivity and specificity in detecting both subjective and objective cognitive impairments. In both crude and multivariable models, the s-MoCA-SWE was more strongly associated than the MoCA with cognitive impairment at 6 months. CONCLUSIONS: Both the short and standard versions of the MoCA appear to be effective in identifying individuals likely to experience persistent cognitive issues following a stroke. Considering the limited time available in an acute stroke unit, the short-form version may be more practical. Nevertheless, further prospective studies are required to validate these findings.

The validity of instruments to measure knowledge in population-based cancer screening targeting individuals at average risk - A systematic review.

OBJECTIVES: Relevant knowledge is essential for informed choices about (non)participation in population-based cancer screening. Many instruments have been proposed to assess residents' knowledge about cancer screening programmes but their measurement properties are unknown. This systematic review aims to identify and critically evaluate the measurement properties of instruments to measure knowledge about cancer screening in individuals eligible for population-based screening. METHODS: A literature search was undertaken in PubMed, PsycINFO, Embase, CINAHL, Scopus and Web of Science in August 2023. The review included any study reporting one or more measurement properties of the questionnaire or sub-scale used measuring knowledge of cancer screening including breast, colorectal and/or cervical cancer screening. Studies including males aged 45 or older and females aged 20 or older were included. Two independent reviewers screened the articles and assessed the included articles using the COnsensus-based Standards for the selection of health Measurement Instruments (COSMIN). RESULTS: We included 24 instruments, which varied in number and characteristics of items. All instruments were assessed as having an inadequate instrument development. The results of structural validity, internal consistency, criterion validity and reliability were assessed as indeterminate, while construct validity and responsiveness were assessed as sufficient. CONCLUSION: This systematic review identified no instruments to measure knowledge about cancer screening where the measurement properties were sufficiently evaluated. There is a lack of focus on content validity and structural validity, and further validation of the instruments is needed. The results indicate a lack of shared understanding or agreement of what constitutes relevant knowledge about cancer screening.