La prescription en biologie clinique : rationaliser sans altérer la qualité

Nowadays, clinical pathology has becoming a central medical discipline in the health care ecosystem and blood sampling is an unavoidable step. Lab testing results influence about 70% of medical decisions. In response to the economic pressure on health care accentuating the need for rationalization in many countries, clinical pathology laboratories must act and implement measures to reduce costs while ensuring that they maintain and respect highest quality standards. Therefore, to target the effective actions to be implemented, it is necessary to identify and define the reasons explaining the observed increase in the budgets devoted to laboratory tests. A whole literature appealing to the notion of "Right order" is available and is a source of inspiration for many authors. What are the concepts behind these words? What does it mean to “What does right order mean”? As part of an analytical approach to review the literature, a search for tools to optimize the prescription of clinical biology will make it possible to establish recommendations for implementing, developing and perpetuating a strategy of “prescribing correctly” with prescribers. An in-depth analysis of the context of use of these tools is thus in order to understand their adaptation and the essential conditions for their implementation in an academic context. Eventually, it will be necessary to define the elements to be introduced into an information management tool (EMR – Electronic Medical Record) to support the learning of “right order” and, through this, achieve the defined objective. Throughout the process, the emphasis is placed on respecting the freedom of the prescriber, who remains the sole judge of the relevance of his ordering act in relation to the particular context of each patient.(SP - Sciences de la santé publique) -- UCL, 202

Éléments cliniques pour orienter la demande de prise de sang

Depuis de nombreuses années, la littérature abonde d’articles ayant pour thème la juste prescription d’examens de laboratoire. En effet, la biologie clinique joue un rôle important dans le diagnostic et le suivi des patients. Face aux contraintes économiques sur les soins de santé, la pression pour réduire les coûts liés à la prescription inappropriée d’examen de laboratoire est importante. Plusieurs facteurs (recommandations de sociétés savantes, expérience, pression des patients, information par rapport aux propriétés intrinsèques des tests de laboratoire) interviennent dans la décision de prescrire et dans le choix du test le plus approprié au contexte clinique du patient. L’apport d’outils informatiques, même s’ils ne remplaceront pas l’acte intellectuel de prescription, permettra le développement d’algorithmes d’aide à la décision clinique.[Clinical elements in guiding the prescription of blood tests] For many years, there has been a plentiful literature focused on the correct prescription of laboratory tests. Clinical biology indeed plays a major role in patient diagnosis and follow-up. Due to the economic constraints faced by the healthcare system, there is a huge pressure aimed at reducing the costs generated by inappropriate laboratory test prescriptions. Several factors (such as guidelines of academic societies, know-how, patient’s urging and information on the intrinsic properties of laboratory tests) play a role in the decision of prescribing tests and in the choice of the most appropriate test based on the patient’s clinical situation. Though not replacing the physician’s intellectual reasoning, IT and computer technologies will help developing decision-making algorithms

Prostate cancer screening: clinical impact of WHO calibration of Beckman Coulter Access (R) prostate-specific antigen assays

Background: The goal of this study was to evaluate the clinical impact of using the same total prostate-specific antigen (tPSA) and free PSA (fPSA) assays calibrated with World Health Organization (WHO) materials or with Hybritech Tandem-R calibrator. Methods: From the initial correlation study that included 150 patients, the clinical impact of the WHO calibration was simulated using a large cohort (n = 4548) of referred patients. Interim reports of the European Study of Screening for Prostate Cancer (ERSPC) were used to evaluate the clinical outcomes of patients and the risk of prostate cancer (PCa). Results: WHO calibration of tPSA assays leads to a reduction of about 20% in measured results (tPSA WHO = 0.81 tPSA Hybritech + 0.04; fPSA WHO = 0.78 fPSA Hybritech + 0.00; %fPSA WHO = 0.92 %fPSA Hybritech + 0.00). The simulation showed that the WHO calibration is associated with a risk of missing 15% of PCa. Conclusions: The discrepancies between the two calibrations lead to significant clinical misinterpretation with decreased detection of PCa if tPSA cut-off thresholds are not adjusted. Clin Chem Lab Med 2010;48: 285-8

How to optimize the prescription of laboratory tests? Success and failures in an academic hospital.

In the context of the flat-rate reimbursements in healthcare, we reviewed physicians' behavior towards laboratory test ordering. We demonstrated how it could be improved when a specific stage of the patient management is considered. We took a multi-step approach to analyze the laboratory test orders in the context of planned laparoscopic cholecystectomy in a general teaching hospital. A reference order set was defined through a collaborative analysis between clinicians and laboratory physicians. The clinical and financial impacts were then evaluated over a period of 24 months. After the introduction of the reference order set, the number of laboratory tests per order decreased significantly for patients with cholecystitis of low severity. Above the monitoring of repeated orderings during a single stay, the major impacts were achieved by a drastic reduction of inappropriate orders, particularly in the field of bacteriology. The main effects of the order set were maintained throughout a follow-up period of 24 months. Our study demonstrated that, when considering laboratory test ordering optimization, reference order sets could achieve high levels of efficiency. To ensure high compliance to reference order sets, extensive collaboration between clinicians and laboratory physician is mandatory even if very sophisticated information systems are available

Comparison of three free T4 (FT4) and free T3 (FT3) immunoassays in healthy subjects and patients with thyroid diseases and severe non-thyroidal illnesses.

Abstract BACKGROUND: Free T4 (FT4) and free T3 (FT3) immunoassays exhibit wide inter-assay variations. We therefore established control values with three different immunoassays and compared their clinical performances in thyroidal diseases and severe/acute non-thyroidal illnesses (NTI). METHODS: The UniCel DxI 800, Architect i2000, and Elecsys 2010 assays were used. FT4 and FT3 reference ranges were established in 68 controls, without conditions interfering with thyroid function, with normal TSH (0.35-3.02 mU/L) and negative anti-thyroid peroxidase antibodies. Free hormones were determined in 60 patients with thyroid diseases (TSH: < 0.001-31.5 mU/L) and 45 NTI patients (TSH: 0.10-4.72 mU/L). Control values were normalized as Z-scores; patients' results were expressed as Z-scores, using the control values of each assay. Pairwise comparisons of the Z-scores were performed by Deming's regression. Classification of patients' results based on 95% control values were evaluated by kappa agreement statistics. RESULTS: Control values for FT4 (pmol/L; geometrical means; 95% confidence intervals) were: 11.1 (7.6-16.1), 12.3 (9.1-16.6), 15.6 (11.4-21.4) and for FT3: 4.8 (4.0-5.7), 4.0 (3.0-5.3), 4.3 (3.1-5.09), with DxI 800, Architect, and Elecsys, respectively. Pairs of control Z-scores correlated significantly, but with different strengths (FT4: r = 0.915, 0.740, 0.770; FT3: r = 0.615; 0.589; 0.790, for DxI 800 vs. Elecsys; DxI 800 vs. Architect; Elecsys vs. Architect; p < 0.001); slopes and intercepts of paired controls were 1.00 and zero. In thyroid diseases, slopes of FT4 Z-scores among assays differed slightly from 1.00 (1.11, 0.88, 0.87 for DxI versus Elecsys, DxI 800 versus Architect, Elecsys versus Architect, respectively; p < 0.05); slopes of FT3 Z-scores were consistent with unity, except for DxI 800 versus Elecsys (0.88; p < 0.05). In NTI patients, regression slopes were consistent with unity (p < 0.05). The agreement statistics showed moderate to very good inter-assay concordances for thyroid and NTI patients' results. CONCLUSIONS: FT4 and FT3 assays show moderate to very good agreement, in patients with thyroid diseases or NTI when compared pairwise to their control values. Slight quantitative differences between some pairs of assays are observed in thyroid diseases, after normalization as Z-scores

Clinical usefulness of the CSF β-amyloid Aβ1-42/Aβ1-40 ratio for Alzheimer's disease diagnosis: a retrospective study in a Belgian academic hospital.

No abstract availabl

Macro vitamin B12: an underestimated threat.

BACKGROUND : The correct identification of the macro-B12 interference (macroforms) is paramount to avoid potential erroneous clinical decisions. Our objectives were to determine whether immunoassays are affected by the presence of macro-B12 and to validate a polyethylene glycol (PEG) precipitation procedure to detect it. METHODS : Sixty-two serum samples obtained from healthy volunteers were analyzed to determine recovery and reference intervals (RIs) following PEG precipitation. Thereafter, 50 serum samples with very high levels of B12 (>1476 pmol/L) were randomly selected to search for macro-B12 interferences. Serum samples obtained from healthy volunteers and related PEG aliquots were analyzed on a Cobas® immunoassay. Patients’ samples were analyzed on both Cobas® and Architect® immunoassays. Finally, samples suspected to contain macro-B12 were analyzed by size-exclusion chromatography (SEC) to confirm the presence of macro-B12. RESULTS : Recovery and post-PEG RIs determined on a Cobas 8000® in healthy volunteers ranged from 68.3% to 108.4% and from 122.1 to 514.4 pmol/L, respectively. Fifteen samples (30%) were found to show macro-B12 while using the recovery criteria, and nine samples (18%) while using the post-PEG RI. The other immunoassay ran on the Architect i2000® was also affected by the presence of macro-B12. Size-exclusion chromatography studies confirmed the presence of macro-B12 (immunoglobulin-B12 complexes). CONCLUSIONS : The prevalence of macro-B12 in elevated B12 samples is high. We suggest to systematically screen for the presence of macro-B12 with PEG precipitation procedure in samples with elevated B12 levels to avoid potential misdiagnosis or harmful clinical consequences