# Instruction for authors

Conflict of interestEthical conduct## General considerations

Biochimica Clinica (BC) publishes papers related to Clinical Biochemistry and Clinical Molecular Biology and generally to Laboratory Medicine. Papers written both in Italian and in English are published.

At the request of the Authors or in the opinion of the Editor, the submitted articles are published in the categories listed below:

- Editorials (by invitation only)
- Reviews (normally by invitation, but suggestions on topics of interest are welcome)
- Research articles
- Opinions
- Documents
- SIBioC Documents
- Case reports
- Letters to the Editor

BC is published in electronic format on a quarterly basis (4 issues per year); in addition, 1 or 2 monographs on topics chosen by the Editorial Committee are published per year.

Format and length of the different types of articles

Type | Abstract/words | Word count | Tables & Figures | N. of references |

Reviews | YES/250 | 6000 | 8 | 150 |

Research articles | YES/250 | 3500 | 8 | 50 |

Opinions | YES/250 | 3500 | 5 | 50 |

Documents | YES/250 | NA | NA | NA |

SIBioC Documents | YES/250 | NA | NA | NA |

Letters to the Editor | NO | 1200 | 2 | 12 |

Case reports | YES/150 | 1500 | 2 | 10 |

The figures in the table should be considered as maximum values. NA, not applicable

Please submit the manuscripts exclusively at online at (https://mc04.manuscriptcentral.com/BiochimClin).

The submitted papers are sent for anonymous review (single blind review) to specialized reviewers chosen by the Associated Editors or by the Editor in Chief. Throughout the editorial process, BC complies with the recommendations of the “International Committee of Medical Journal Editors” ( www.icmje.org) and with the ethical standards of the "Committee on Publication Ethics" (COPE, publicationethics.org).

Articles that do not fall within the scope of the journal or that deal with topics already widely debated in the scientific literature can be rejected without peer review. Manuscripts that are not in line with the standards listed below are sent back to the Authors for the necessary modifications.

In preparing the manuscript, the Authors must adhere to precise ethical rules, as detailed in the Declaration on ethics. Particular attention must be paid to:

- filling in the conflict-of-interest form (mandatory)
- adherence to the Declaration of Helsinki (when appropriate)
- approval of the Institution's Ethics Committee (when appropriate)
- presence of the informed consent (when appropriate)
- originality of the work (submitted manuscripts are subject to anti-plagiarism check)

## INSTRUCTION

The language used in the text must be concise but informative, paying attention to the scientific terminology and avoiding slang expressions. Manuscripts must be reviewed by a native English speaker expert in the field, to ensure an adequate linguistic level.

Abbreviations must be reported in brackets, after the full expression, the first time they appear in the text. Subsequently, only the abbreviation should be reported in the text.

Units of measurement must be correct and in line with the International System of Measurement.

For concentration units (mass, substance, activity, number), use the liter (L) in the denominator. The values must be reported with the number of relevant figures, consistent with the intrinsic variability of the measurements; the decimal digits must be separated with a point.

## Manuscript preparation

**Cover letter: **It should include the Title of the manuscript, full name of the Authors and their affiliation. It must be signed by the corresponding Author, whose address must be clearly indicated, complete with telephone number and e-mail address. It must also be specified that all the Authors approve the manuscript content and agree with the submission of the paper. In addition, the Author can indicate the preferred category of the journal for the publication of the contribution. The author must also declare that the manuscript is original and is not being evaluated by any other journal. The cover letter is not shared with the reviewers

**Title:** It must be concise but self-explanatory of the article contents. In general, it should not include acronyms or abbreviations.

**Author(s):** Full name and surname, and correct affiliation.

**Abstract: **An Abstract of maximum 250 word is mandatory except for Editorials and Letters to the Editor**; **Research Articles require a structured Abstract (Introduction, Methods, Results, Discussion).

The other types of manuscripts DO NOT require structured abstracts.

**Keywords**Indicate three keywords preferably using the MeSH terms (www.ncbi.nlm.nih.gov/mesh).

For manuscripts intended for sections other than Research Articles, the subdivision into the chapters mentioned below is not necessary; however, Introduction and Discussion (or Conclusions) are normally necessary paragraphs.

**Introduction:** Brief description of the background of the research, with references to the relevant literature, followed by an indication of the purpose of the work.

**Methods:** Fully describe the population enrolled in the study (subjects or patients), chemical and biological reagents, diagnostic kits, calibrators, control materials, analytical instruments and systems, analytical methods; include a paragraph describing statistical methods. If commercial reagents and analytical systems in current use are used, it is sufficient to indicate the principle of the method and the commercial analytical system used. The instrumentation and diagnostic kits used must be followed by the name of the manufacturer, town and Country.

When using statistical methods, follow the indications given at the end of these Instructions.

In the case of studies involving human subjects or patients and/or biological samples from human subjects, a declaration (to be inserted in the text) is mandatory that during the study the Declaration of Helsinki dated 1975, as amended in 2013, was respected and applied (Declaration of Helsinki – WMA – The World Medical Association) and, in the case of biological samples collected for the purpose, a specific Informed Consent was obtained from each of the subjects enrolled in the study.

**Results:** These must be reported concisely, with a logical sequence that reflects the purpose of the work, with precise references to the included iconography (tables and figures). Numerical values resulting from measurements must always be followed by the corresponding unit of measurement. The results can be reported in tables (if the focus is on the figure’s detail, or if they are observations/descriptions) or in figures/graphs (when a quick global evaluation is important, or when there is no other possibility). For the same dataset use either one or the other, not both.

**Tables:** They must be sorted in rows and columns; each column must have a clear heading, including the units of the numerical values. Each table must be produced on a single page __separated from the text__the relative caption preceded by the table number must be shown on the page at the top of the table. The caption should be succinct but informative, in the format exemplified here: "Table 1. Data relating to the different groups studied". The tables must be numbered consecutively in Arabic numerals, starting with 1, in the order of citation in the text. Do not duplicate the data in the text.

**Figures:** They must be of such quality to allow their direct reproduction, taking into account the inevitable reduction. Figures in black and white or in colour can be sent; the editorial secretariat, in agreement with the EIC, will evaluate the reproduction methods (black and white or in colour). In the case of graphs, attention should be paid to a correct representation and the correct expansion of the axes. Computerized typesetting is recommended, with an appropriate graphics program. Do not send 3D graphics. The figures must be numbered consecutively in Arabic numerals, starting from 1, according to the order of citation in the text and must be sent in a separate file (not included in the main document). Each figure must be accompanied by a caption: all captions, preceded by the number of the respective figure, must be reported in order on a single page, separate from the figures. Do not duplicate the data in the text

**Discussion:** The meaning of the results achieved with regard to the purpose of the work, hypotheses reported in the literature, hypotheses issued, any concordance or discrepancy with previous observations should be included. Report hints of clinical and/or analytical interpretation of the results. End with a brief conclusion, mentioning if the aim of the paper has been achieved or not, and the possible practical significance of the obtained results.

**References:** They should be numbered consecutively according to the order of citation in the text, starting with 1. The sequence number should appear in the text (in parentheses) where appropriate. Report in full all the names of the Authors of each paper up to a maximum of six. If more than six, report the first six followed by "et al." Indicate journal by abbreviation provided at www.ncbi.nlm.nih.gov/nlmcatalog/journals/

The individual entries must be reported in the style exemplified below, paying attention to correct punctuation.

__Articles in journals (up to six Authors__: Lindahl TL, Egberg N, Hillarp A, Odegaard OR, Edlund B, Svensson J, et al. INR calibration of Owren-type prothrombin time based on the relationship between PT% and INR utilizing normal plasma samples. Thromb Haemostasis 2004;91:1223–31.

__Articles in journal with more than 6 Authors__): Lindahl TL, Egberg N, Hillarp A, Odegaard OR, Edlund B, Svensson J, et al. INR calibration of Owren-type prothrombin time based on the relationship between PT% and INR utilizing normal plasma samples. Thromb Haemostasis 2004;91:1223–31.

__Articles ahead of print:__ Liu L, Cai X, Love T, Matthew Corsetti M , Andrew M. Mathias AM et al. Using logistic regression models to investigate the effects of high-sensitivity cardiac troponin T confounders on ruling in acute myocardial infarction. Clin Chem Lab Med 2023 doi: 0.1515/cclm-2022-1004 (ahead of print).

__Articles in on-line only journals__Arjun MC, Singh AK, Pal D, Das K, Venkateshan M, Mishra B, et al. Characteristics and predictors of Long COVID among diagnosed cases of COVID-19. Plos One 2022 Dec 20;17:e0278825.

__Editorials: __Plebani M, Basso D, Lippi G. Biomarkers of inflammatory bowel disease: ready for prime time? [Editorial] Clin Chem Lab Med 2015;53:1881-2.

__Letters to the Editor: __Paleari R, Santini G, Mosca A. Glycated albumin stability in frozen samples. [Letter] Biochim Clin 2022;45:180-1.

__Supplements__: Sturgeon CM, Al-Sadie R, Unsworth N. External quality assessment of maternal serum screening schemes. A view from UK NEQAS. Biochim Clin 2022;46:Suppl1:S96-S103.

__Books__: Constantin E, Schnell A, eds. Mass spectrometry. Chichester: Ellis Horwood Limited, 1991.

__Chapters in books:__ Barrati J, Ettalbi M. Thermostable insulinases from A. ficcum. In: Fusch A, ed. Insulin and insulin-containing crops. London: Elsevier Science Publisher, 1993:211-6.

Websites: NICE guideline. Cardiovascular disease: risk assessment and reduction, including lipid modification. Available at: https://www.nice.org.uk/guidance/cg181/resources/cardiovascular-disease-risk-assessment-and-reduction-including-lipid-modification-pdf-35109807660997. (Last accessed: January 2023).

__ISO Documents__: ISO14971.2012 Medical devices: application of risk management to medical devices. International Organization for Standardization: Geneva 2012.

__CLSI Doucments:__ Clinical Laboratory Standards Institute (CLSI). Procedures for collection of diagnostic blood specimens by venipuncture; approved guideline, 6^{th} ed. CLSI document H3-A6. CLSI Wayne, PA, 2007.

## CASE REPORT

These contributions require a definite structure.

**Abstract:** maximum 150 words.

**Case Report presentation:** maximum 500 words, This section should include: a description of the case with a definition of the clinical matter (diagnostic, prognostic, monitoring): a brief description of the laboratory tests performed; the logical path followed to obtain conclusions, with specific references to the clinical relevance of the laboratory data obtained.

**Case discussion:** 1000 words maximum. This section should include: a succinct review of the disease in question, the description of the peculiarity of the case, containing a clear reference to the role played by the laboratory tests.

## POST-ACCEPTANCE

Typesetting: it is possible that some formal modifications are made to the manuscript to adapt it to the editorial style of BC. The proofs of the article are sent to the Corresponding Author for the final approval. At this stage, only corrections related to editing or typesetting accuracy are allowed.

Online publication: the article is published online on the journal website, as soon as the approved draft is returned to the secretariat. The correspondence author receives communication of the publication accompanied by the pdf of the article. The article is then inserted in an issue according to the acceptance date (within the same type of contribution).

Copyright: the copyright of an accepted work is automatically transferred to SIBioC; consequently, any reproduction, even of parts of the article itself, requires prior authorization from the copyright holder (in the person of the President of the Society).

## CONFLICT OF INTEREST

Each manuscript must be accompanied by a declaration of conflict of interest.

According to ICJME, there is a conflict of interest when an author (or his/her institution) has a financial relationship (employment, consultancy, ownership of shares, fees, or expert reports) or personal relationship (academic competition, or intellectual position) that may inappropriately influence his/her actions. When submitting a manuscript, all the Authors are requested to fill in the Conflict of Interest Disclosure Form.

## STATISTICAL GUIDELINES

These guidelines are designed to help Authors to prepare statistical data for publication in Biochimica Clinica and are not a substitute for the detailed guidance required to design a study or perform a statistical analysis.

Please refer to specific guidelines for describing results of specific study designs (e.g. observational studies, randomized clinical trials), available at the EQUATOR Network website (1).

Each section of a scientific paper is addressed separately.

**Abstract:** sample size and main results of the study (estimated parameters, group comparisons, associations) must be reported by relevant descriptive statistics, mean or median, standard deviation (SD) or interquartile range (IQR), confidence interval (CI95%) and p value. Moreover, it is also advisable to report the raw (unstandardized) or standardized effect size (2).

**Methods:** the main guiding principle for statistical reporting should be to describe statistical methods with enough detail to enable a knowledgeable reader with access to the original data to verify the reported results. Authors should describe the experimental design, primary and secondary (surrogate and/or intermediate) endpoints, subject selection (inclusion and exclusion criteria), randomization and blinding procedures (1). Sample size should be reported with data needed for its calculation (alpha, power, effect). Methods used for dealing with missing, censored (e.g. results lower than limit of sensitivity) or aberrant data should be described with the total amount (or percentage) of the results affected. Statistical tests and methods used to verify assumptions (e.g. homoscedasticity, or homogeneity of variance, and normality) should be reported. If data were transformed to normalize the distribution, describe the mathematical transformation (log, power) applied with graphical and statistical methods used to verify the Gaussian model before and after transformation. References for statistical methods, unless unusual, are not required. However, it is mandatory to report the statistical software used (name, version, Company’s data).

**Results:** if not described in previous sections, report total sample and group sizes and the number of subjects for each phase of the study design (subjects assessed for eligibility, excluded, randomized, allocated to treatments, lost to follow-up) (1). Relative frequencies, percentages or any other calculated ratio should be reported together with numerators and denominators. Relative frequencies should be reported with two significant figures (e.g. 0.37; 0.026); percentages should not be expressed with more than one decimal place and should be avoided when dealing with small samples (N <10). If observations have been organized into classes, lower and upper class limits should be unambiguously stated. Descriptive statistics require an additional digit than those used for the raw data. Normally distributed data should be described by mean, SD and/or %CV and expressed as **“mean (SD)”** and not as “mean±SD”. When data are not normally distributed, or show a skewed distribution, median and interquartile range (25° - 75° percentiles) should be used instead of mean and SD. If a mathematical transformation has been applied, summary statistics should be carried out on the transformed data and then transformed back to the original scale for presentation (mean and interval limits, but not standard deviation, can be back transformed).

Bar graphs can be used only to describe counts, relative frequencies or percentages but not means or other summary statistics. With continuous variables, best choices are histograms, Box and Whisker plot or dotplot (the latter with small sample size, N <20). Do not use 3D graphs.

When comparing two groups with the Student's t-test, authors should report mean and SD for each group, difference between means with the 95% confidence interval, degrees of freedom, the t-value and the p value. A measure of effect size, such as Cohen’s d, may be further specified (2).

When dealing with more than two groups authors should use the ANOVA test, reporting mean and SD for each group, degrees of freedom, the F-value and the overall p value. If this is not statistically significant, then multiple comparisons must not be applied. If it is significant, multiple-comparison post-hoc correction should be applied (e.g. Bonferroni’s correction or Tukey).

When reporting association between variables (e.g. by chi-squared test, Fisher's exact test), authors should clearly indicate variables, a correct summary statistic, degrees of freedom, the test value and the p value. When the chi-square assumptions are violated, the Fisher’s exact test should be preferred. Reporting an additional measure of size effect (e.g. phi or Cramer’s V) is advisable (2).

For correlation analysis, specify the type of correlation used (Pearson or Spearman), the correlation coefficient with its 95% confidence interval and the t-test (degrees of freedom, t-value and p value). Do not use correlation analysis for analytical method comparison. In these cases, regression analysis (Deming or non-parametric Passing-Bablok) and the Bland-Altman plot should be preferred (3-4).

For linear regression, authors should report ANOVA table results (degrees of freedom, F-value and p value), the equation parameters (slope and intercept) with their 95% confidence intervals and the coefficient of determination R2 .^{2}.

With more complex statistical models (multiple regression, ANOVA models) it is necessary to report the verification of assumptions, the overall p value of the model and model parameters arranged in tabular form (including parameter estimates, confidence intervals, p values). Reporting an additional measure of size effect (e.g. omega-squared) may be useful (2).

Paired data should be analyzed with specific tests. When using non-parametric tests, authors should evaluate variable distribution by graphical methods or formal statistical tests.

p values must be reported with 1 or 2 significant figures. Describing p values as p 0.05 or NS (not significant) should be avoided. If the results are highly significant and the calculated p value is reported by the software as 0.000, then the use of p <0.0005 or p <0.001 is acceptable. Confidence intervals should be stated also for non-significant results. If one of the limits of the confidence interval is negative, report it as “X to Y”.

The conventional use of statistical significance is p <0.05. If a different significance level is used, then reasons for this must be clearly stated in the statistical method section.

**Discussion:** statistical significance should not be equated to clinical importance; similarly, non-statistical significance should not be interpreted as no difference or no effect. Indeed, the lack of statistical significance may be due to small sample size and hence to a low statistical power. Moreover, p values should not be compared among different statistical tests. Association between variables should not be interpreted as causation without additional evidence.

**Further readings:** the SAMPL Guidelines (5).

**References**

- EQUATOR Network: https://www.equator-network.org/ (last access: January 2021).
- Ialongo C. Understanding the effect size and its measures. Biochemia Medica 2016;26:150–63.
- Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986;8476:307-10.
- Vidali M, Tronchin M, Dittadi R, per il Gruppo di Studio SIBioC - Medicina di Laboratorio “Statistica per il laboratorio. Protocol for the comparison of two laboratory methods. Biochim Clin 2016;40:129-42.
- Lang TA, Altman DG. Basic statistical reporting for articles published in biomedical journals: the "Statistical Analyses and Methods in the Published Literature" or the SAMPL Guidelines. Int J Nurs Stud 2015;52:5-9.

## CONTACTS

e-mail: biochimica.clinica@sibioc.it

Editorial secretariat of Biochimica Clinica

Telehone 0245498282 int. 216 ; 3356159776

*Last Revision: March 2023*