Properties and units in the clinical laboratory sciences part XXIV. Properties and units in clinical molecular genetics (technical report 2017).

This document describes the application of the syntax, semantic rules, and format of the Nomenclature for Properties and Units (NPU) terminology for coded dedicated kinds-of-property in the subject field of clinical molecular genetics. A vocabulary for NPU definitions in this field, based on international terminology and nomenclature, is introduced; examples of actual NPU definitions for different types of investigations are given and explained.

La normalización en ciencias de laboratorio clínico / Standardisation in clinical laboratory sciences

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Estimation of Alert and Change Limits of Haematological Quantities and its Application in the Plausibility Control.

INTRODUCTION: In the process of quality assurance of the measured values of the clinical laboratory, one of the purposes is to perform the validation of patients' measured values in the most objective way. This validation process is called plausibility control which may be defined as the set of procedures used to decide if a patient's measured value is valid according to established clinical and biological criteria. The aim of this study is to propose a model to estimate alert and change limits of measured values of the blood cell count, to be applied to detect doubtful patients' measured values. METHODS: Some alert and change limits were estimated from the emergency laboratory database of the year 2010 using different percentiles. A verification of the suitability of the proposed model was also performed. RESULTS: Most of the fractions of the measured values excluded by the alert and change limits were according to the theoretical expected. The overall fraction of the number of doubtful clinical laboratory reports ranged between 0.6 and 47.6 %. CONCLUSIONS: The proposed model helps, improves and standardizes the process of detection of doubtful measured values since they are produced objectively. These limits can also be configured in a laboratory information system letting the clinical laboratory professional staff to save time and efforts.

Concentration and content.

One of the more frequent activities in health sciences is the measurement of biological quantities. Frequently, when reading biomedical books and journals some confusion on the metrological meaning of biological quantities related to the concepts 'concentration' and 'content' may be observed. Classically, a concentration is an amount of any type per volume of liquid or gas system, whereas content is an amount of any type per mass of liquid or gas or solid system. However the concepts 'concentration' and 'content' alone are still ambiguous because, depending on the type of amount of the component (analyte) per volume or mass of a system, there are different types of concentrations and contents. This article attempts to give a clarification of these concepts, mainly based on international recommendations about nomenclature and terminology of metrology, chemistry and clinical laboratory sciences.

Taxonomy of quantities.

The adjectives "generic", "subgeneric", "specific", and "individual" are proposed to be added to the term "quantity", depending on the case, in order to diminish the ambiguity of this term and to classify the different types of quantities.

Valores de referencia biológicos, acreditación y armonización / Biological reference values; accreditation and harmonisation

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Significance of a change between two consecutive measured values.

BACKGROUND: The interpretation of a change between two consecutive measured values of a given quantity in the same patient is still controversial and it is not commonly found in clinical laboratory reports. We present here a manageable and affordable approach for all clinical laboratories to help physicians to interpret these differences. METHODS: We selected all pairs of two consecutive measured values of serum albumin concentration and serum thyrotropin concentration, both within the biological reference interval, delivered by our clinical laboratory in a 2-year period (2008-2009). We calculated the relative difference between pairs from which we estimated percentiles 2.5 and 97.5 in order to set an interval defining the significance of a change. We verified these intervals with data from the year 2010. RESULTS: During the 2-year period, we found 122,626 consecutive pairs of serum albumin concentration and 9 374 pairs of serum thyrotropin concentration, with both measured values within our biological reference interval. The intervals defining the significance of a change between two consecutive measured values were: (-14.0 to 17.6)% for the relative differences of albumin concentration, and (-61.4 to 177.8)% for the differences of thyrotropin concentration, which determined 12.7% and 18.4% of significant relative differences, respectively. Similar results were obtained from data for the year 2010. CONCLUSIONS: The interval that defines the significance of a change could easily be estimated with the patients' measured values obtained daily in the laboratory. Our proposal is more appropriate to each specific population than the conventional intra-individual biological variation approach.

Proposed criteria for sorting examined properties in clinical laboratory reports.

To date not much importance has been given to the sorting of examined properties ("tests") in clinical laboratory reports. The present article contains a proposal about sorting the examined properties of clinical laboratory reports, in order to facilitate their interpretation to the requesting physicians. This proposal is mainly based on clinical and patho-physiological criteria. A set of groups of properties has been established according to the main clinical indications of each property. Some of these properties have several clinical indications and, consequently, have been included in more than one group. Some of these groups have been associated to other groups, so that the properties conforming them will always appear consecutively, since they are patho-physiologically related. Finally, an association between each group with the different medical specialities or areas of knowledge has been made, according to the clinical indications of each property. The groups of properties proposed are in concordance with their main clinical indications and their patho-physiological relationship. This ordering system gives priority, first, to the alarm (critical) values and, second, to the medical speciality or knowledge area of the requesting physician. This proposal can help the requesting physician to see first of all the most relevant clinical laboratory information related to her/his patient.

An outline for a vocabulary of nominal properties and examinations--basic and general concepts and associated terms.

Scientists of disciplines in clinical laboratory sciences have long recognized the need for a common language for efficient and safe request of investigations, reporting of results, and communication of experience and scientific achievements. Widening the scope, most scientific disciplines, not only clinical laboratory sciences, rely to some extent on various nominal examinations, in addition to measurements. The 'International vocabulary of metrology--Basic and general concepts and associated terms' (VIM) is designed for metrology, science of measurement. The aim of the proposed vocabulary is to suggest definitions and explanations of concepts and terms related to nominal properties, i.e., properties that can be compared for identity with other properties of the same kind-of-property, but that have no magnitude.