There is a need for standards for generation and reporting of Biological Variation (BV) reference data. The absence of standards affects the quality and transportability of BV data, compromising important clinical applications. To address this issue, international expert groups under the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) have developed an online resource (https://tinyurl.com/bvmindmap) in the form of an interactive mind map that serves as a guideline for researchers planning, performing and reporting BV studies. The mind map addresses study design, data analysis, and reporting criteria, providing embedded links to relevant references and resources. It also incorporates a checklist approach, identifying a Minimum Data Set (MDS) to enable the transportability of BV data and incorporates the Biological Variation Data Critical Appraisal Checklist (BIVAC) to assess study quality. The mind map is open to access and is disseminated through the EFLM BV Database website, promoting accessibility and compliance to a reporting standard, thereby providing a tool to be used to ensure data quality, consistency, and comparability of BV data. Thus, comparable to the STARD initiative for diagnostic accuracy studies, the mind map introduces a Standard for Reporting Biological Variation Data Studies (STARBIV), which can enhance the reporting quality of BV studies, foster user confidence, provide better decision support, and be used as a tool for critical appraisal. Ongoing refinement is expected to adapt to emerging methodologies, ensuring a positive trajectory toward improving the validity and applicability of BV data in clinical practice.

Robust reference data, representing a large and diverse population, are needed to objectively classify measurements of spondylolisthesis and disc space narrowing as normal or abnormal. The reference data should be open access to drive standardization across technology developers. The large collection of radiographs from the 2nd National Health and Nutrition Examination Survey was used to establish reference data. A pipeline of neural networks and coded logic was used to place landmarks on the corners of all vertebrae, and these landmarks were used to calculate multiple disc space metrics. Descriptive statistics for nine SPO and disc metrics were tabulated and used to identify normal discs, and data for only the normal discs were used to arrive at reference data. A spondylolisthesis index was developed that accounts for important variables. These reference data facilitate simplified and standardized reporting of multiple intervertebral disc metrics.

K-562 is a well-known in vitro cellular model that represents human leukemia cell lines. Although the K-562 cells have been extensively characterized, there are inconsistencies in the data across publications, showing the presence of multiple K-562 cell lines. This suggests that analyzing a single K-562 cell line is insufficient to provide reliable reference data. In this study, we compared three K-562 cell lines with different IDs (RCB0027, RCB1635, and RCB1897) to investigate the fundamental characteristics of K-562 cells. Amplifications of the BCR-ABL1 fusion gene and at 13q31 were detected in all three cell lines, whereas each genome exhibited distinctive features of sequence variants and loss of heterozygosity. This implies that each K-562 cell line can be characterized by common and unique features through a comparison of multiple K-562 cell lines. Variations in transcriptome profiles and hemoglobin synthesis were also observed among the three cell lines, indicating that they should be considered sublines that have diverged from the common ancestral K-562 despite no changes from the original cell name. This leads to unintentional differences in genotypes and/or phenotypes among cell lines that share the same name. These data show that characterizing a single K-562 cell line does not necessarily provide data that are applicable to other K-562 cells. In this context, it is essential to modify cell names in accordance with changes in characteristics during cell culture. Furthermore, our data could serve as a reference for evaluating other K-562 sublines, facilitating the discovery of new K-562 sublines with distinct characteristics. This approach results in the accumulation of K-562 sublines with diverged characteristics and expands the options available, which may help in selecting the most suitable K-562 subline for each experiment.

We compared methods to project absolute risk, the probability of experiencing the outcome of interest in a given projection interval accommodating competing risks, for a person from the target population with missing predictors. Without missing data, a perfectly calibrated model gives unbiased absolute risk estimates in a new target population, even if the predictor distribution differs from the training data. However, if predictors are missing in target population members, a reference dataset with complete data is needed to impute them and to estimate absolute risk, conditional only on the observed predictors. If the predictor distributions of the reference data and the target population differ, this approach yields biased estimates. We compared the bias and mean squared error of absolute risk predictions for seven methods that assume predictors are missing at random (MAR). Some methods imputed individual missing predictors, others imputed linear predictor combinations (risk scores). Simulations were based on real breast cancer predictor distributions and outcome data. We also analyzed a real breast cancer dataset. The largest bias for all methods resulted from different predictor distributions of the reference and target populations. No method was unbiased in this situation. Surprisingly, violating the MAR assumption did not induce severe biases. Most multiple imputation methods performed similarly and were less biased (but more variable) than a method that used a single expected risk score. Our work shows the importance of selecting predictor reference datasets similar to the target population to reduce bias of absolute risk predictions with missing risk factors.

OBJECTIVE: Motion analysis is crucial for effective and timely rehabilitative interventions on people with motor disorders. Conventional marker-based (MB) gait analysis is highly time-consuming and calls for expensive equipment, dedicated facilities and personnel. Markerless (ML) systems may pave the way to less demanding gait monitoring, also in unsupervised environments (i.e., in telemedicine). However,scepticism on clinical usability of relevant outcome measures has hampered its use. ML is normally used to analyse treadmill walking, which is significantly different from the more physiological overground walking. This study aims to provide end-users with instructions on using a single-camera markerless system to obtain reliable motion data from overground walking, while clinicians will be instructed on the reliability of obtained quantities.
METHODS: The study compares kinematics obtained from ML systems to those concurrently obtained from marker-based systems, considering different stride counts and subject positioning within the capture volume.
RESULTS: The findings suggest that five straight walking trials are sufficient for collecting reliable kinematics with ML systems. Precision on joint kinematics decreased at the boundary of the capture volume. Excellent correlation was found between ML and MB systems for hip and knee angles (0.92CONCLUSIONS: Single-camera markerless motion capture systems have great potential in assessing human joint kinematics during overground walking. Clinicians can confidently rely on estimated joint kinematics while walking, enabling personalized interventions and improving accessibility to remote evaluation and rehabilitation services, as long as: (i) the camera is positioned to capture someone walking back and forth at least five times with good visibility of the entire body silhouette; (ii) the walking path is at least 2 m long; and (iii) images captured at the boundaries of the camera image plane should be discarded.

OBJECTIVE: Due to the demographic shift, the number of older people suffering from hearing loss and from cognitive impairment increases. Both are closely related and hard to differentiate as most standard cognitive test batteries are auditory-based and hearing-impaired individuals perform worse also in non-auditory test batteries. Therefore, reference data for hearing-impaired are mandatory.
METHODS: The computer-based battery ALAcog assesses multiple cognitive domains, such as attention, (delayed) memory, working memory, inhibition, processing speed, mental flexibility and verbal fluency. A data set of 201 bilaterally hearing-impaired subjects aged ≥ 50 (mean 66.6 (SD 9.07)) was analysed. The LMS method, estimated curves for the 10th, 25th, 50th, 75th and 90th percentile were calculated, and classified according to age, starting from the age of 50.
RESULTS: Cognitive function shows a decline in all subtests as people age, except for verbal fluency, which remains almost stable over age. The greatest declines were seen in recall and delayed recall and in mental flexibility. Age and hearing ability did not correlate (p = 0.68). However, as people age, inter-subject variability of cognitive test results increases. This was especially the case for inhibition. Cognitive function was not correlated with hearing ability (each p ≥ 0.13).
CONCLUSIONS: The present results make an approach to establish reference data for a comprehensive non-auditory test battery in a large sample of elderly hearing-impaired people which can be used as a simple tool to better contextualise cognitive performance beyond mean and median scores.

Artificial intelligence (AI)-based applications for the assessment of the paediatric musculoskeletal system like BoneXpert are not only useful to assess bone age (BA) but also to provide a bone health index (BHI) and a standard deviation score (SDS) for both. This allows comparison of the BHI with age- and sex-matched healthy Caucasian children.
We conducted this study with the objective of generating BHI curves using BoneXpert in healthy Indian children with BA between 2 and 17 years.
We retrospectively reviewed anthropometric parameters, BHI, and BHI SDS data of digitalized left-hand radiographs (joint photographic experts group [jpg] format) of a cohort of 788 paediatric patients from a previous study to which they were recruited to compare various methods of BA assessment. The recruited children represented all age groups for both sexes. The corrected BHI for jpg images was calculated using the formula corrected BHI=BHI*(stature/(avL*50))^0.33333 where stature is height of subject and avL is average length of metacarpal bones. The reference Indian BHI curves and centiles were generated using the Lambda-Mu-Sigma method.
The mean BHI and BHI SDS of the study group were 4.02±0.57 and -1.73±1.09, respectively. The average increase in median BHI from each age group was between 2.5% and 3% in both sexes up to age of 14 years after which it increased to 4.5% to 5%. The mean BHI of Indian children was lower than that of Caucasian children with maximum differences noted in boys at 16 years (21.7%) and girls at 14 years (16%). We report 8.4% SD of BHI for our study sample. Reference percentile curves for BHI according to BA were derived separately for boys and girls.
Reference data has been provided for the screening of bone health status of Indian children and adolescents.

OBJECTIVE: The aim of the study was to analyze orbitofacial anthropometric parameters such as inner and outer canthal distances (ICD and OCD), palpebral fissure length (PFL), interpupillary distance (IPD), and canthal index (CI) in children with pseudostrabismus and to compare the measured IPD (mIPD) with calculated IPD (cIPD).
METHODS: This was a prospective study of sixty children (6 months-18 years) with pseudostrabismus. ICD, OCD, PFL, and IPD were measured by digital Vernier caliper. The formula used was cIPD: 0.21+0.24 ICD+0.58°CD for males and 1.4+0.31 ICD+0.41°CD for females. Values measured by caliper were compared with that calculated by the formula. The formula used was CI: ICD × 100/OCD. Data were analyzed statistically.
RESULTS: The mean age was 6.66 ± 3.57 years. Telecanthus was the most common finding (55%). The mean ICD and OCD in males were 30.89 ± 3.33 mm and 87.96 ± 8.09 mm and in females were 30.91 ± 3.05 and 86.22 ± 6.81 mm, respectively. The mean right eye PFL in males was 28.53 ± 2.63 mm and in females was 27.66 ± 2.22 mm and left eye PFL in males was 28.53 mm ± 2.63 and in females was 27.66 ± 2.22 mm. CI in males was 35.10 ± 1.65 and in females was 35.84 ± 1.71. Mean mIPD and cIPD: male - 55.37 ± 4.75 mm and 58.56 ± 5.34 mm, female - 53.32 ± 4.74 mm and 46.26 ± 3.71 mm. A good agreement was found between mIPD and cIPD.
CONCLUSIONS: This study helps in documenting the anthropometric pattern of the orbitofacial parameters in children with pseudostrabismus which can act as reference data. This helps in the management of orbitofacial, craniofacial syndromes/deformities and lid reconstructive surgeries in retaining ethnical features and obtaining better function. In children\'s spectacle frame 1 and lens making, where measuring IPD is difficult, cIPD can be a simple alternative.

UNASSIGNED: The Foot and Ankle Outcome Score (FAOS) is widely used in clinical practice and research. However, FAOS reference values are missing to aid interpretation. This study aimed to establish national record-based reference values for the FAOS.
UNASSIGNED: A national representative sample of 9996 adult Danish citizens was derived from the Danish Civil Registration System. The FAOS questionnaire was sent to all participants, including 2 supplemental questions regarding previous foot and ankle problems and body mass index (BMI). A threshold of 10 FAOS points was predefined as a clinically relevant difference across all 5 subscales.
UNASSIGNED: A total of 2759 participants completed the FAOS. Mean age of participants was 60.5 years, and 51% were women. The mean FAOS subscale scores were as follows: pain, 87.1 (95% CI 86.4-87.8); symptoms, 85.1 (95% CI 84.5-85.8); activity of daily living (ADL), 88.9 (95% CI 88.2-89.6); sport and recreation function 78.5 (95% CI 77.4-79.6); and quality of life (QOL), 79.9 (95% CI 79.0-80.9). The mean difference between men and women was small and not clinically relevant (ranged from 0.9 in ADL to 3.4 in QOL). The largest differences in mean scores between age groups ranged from 4.3 in symptoms to 16.4 in sport/rec. Except for the subscale sport/rec, all age-related differences were below the predefined threshold of 10 for clinical relevance. The difference in mean subscale scores between the lowest BMI group (<24.7) and the obese group (>30) ranged from 19.6 in ADL to 39.1 in sport/rec.
UNASSIGNED: We found in our population that BMI severely impacted FAOS scores. We recommend using BMI-specific reference FAOS values. Separate FAOS reference values for men and women appear not needed. Stratifying reference values for age is likely not needed except for the subscale sport and recreation function.
UNASSIGNED: Level III, cohort study.

To establish the extent of agreement for ISCEV standard reference pattern reversal VEPs (prVEPs) acquired at three European centres, to determine any effect of sex, and to establish reference intervals from birth to adolescence.
PrVEPs were recorded from healthy reference infants and children, aged 2 weeks to 16 years, from three centres using closely matched but non-identical protocols. Amplitudes and peak times were modelled with orthogonal quadratic and sigmoidal curves, respectively, and two-sided limits, 2.5th and 97.5th centiles, estimated using nonlinear quantile Bayesian regression. Data were compared by centre and by sex using median quantile confidence intervals. The \'critical age\', i.e. age at which P100 peak time ceased to shorten, was calculated.
Data from the three centres were adequately comparable. Sex differences were not clinically meaningful. The pooled data showed rapid drops in P100 peak time which stabilised by 27 and by 34 weeks for large and small check widths, respectively. Post-critical-age reference limits were 87-115 ms and 96-131 ms for large and small check widths, respectively. Amplitudes varied markedly and reference limits for all ages were 5-57 μV and 3.5-56 μV for large and small check widths, respectively.
PrVEP reference data could be combined despite some methodology differences within the tolerances of the ISCEV VEP Standard, supporting the clinical benefit of ISCEV Standards. Comparison with historical data is hampered by lack of minimum reporting guidelines. The reference data presented here could be validated or transformed for use elsewhere.