[For an efficient and reasonable accreditation of allergen specific IgE]. / Pour une accréditation efficace et raisonnable du dosage des IgE spécifiques d'allergènes.

French medical laboratories must be accredited before November 2016 according to NF/EN/ISO 15189 standard. However, technical accreditation guidelines cannot be applied literally for the determination of specific IgE for several reasons: more than 600 allergen tests, lack of international gold standard, limited external quality controls. Furthermore, the technique for determination of specific IgE is CE DM-IVD marked, common to all specificities, automatised, standardized according to a single calibration curve. Thus, we propose an efficient but reasonable solution conform to the idea of the accreditation by validating the process. We recommend: a flexible extend type A; choice of only one representative allergen (Dermatophagoides pteronyssinus) for repeatability and precision (20 tests, 2 levels 0.5-1 and 8-12 kUA/L) performed on patients sera, reproducibility (30 consecutive determinations using an Internal Quality Control/IQC), accuracy (IQC and rare External Quality Controls) compared with peers. Sensitivity, specificity, dynamic range, detection threshold are determinated by the provider. Linearity may be checked if the laboratory practices sample dilution for values higher than the upper limit guaranteed by the provider. In the absence of international gold standard, the uncertainty is not measurable. In case of change of instrument, the results obtained by the systems must be compared through 35 tests of different specificities distributed across the range of calibration and including 5 values close to the detection limit. This methodology allows a scientifically effective verification, technically and financially reasonable, to ensure the excellence of the performance of the laboratory with regard to peers and users (allergologists and patients).

Cortisol levels and adrenal reserve after successful cardiac arrest resuscitation.

The postresuscitation phase after out-of-hospital circulatory arrest shares similarities with severe sepsis. Corticosteroid replacement is beneficial in patients with septic shock and adrenal dysfunction. The goal of this study was to assess baseline cortisol and adrenal reserve of out-of-hospital circulatory arrest patients after recovery of spontaneous circulation. Thirty-three consecutive patients successfully resuscitated after cardiac arrest were prospectively included between March 2002 and June 2003. A serum cortisol assay and a corticotropin test (250 microg i.v.) were done 6 to 36 h after circulatory arrest. A cortisol increase smaller than 9 microg/dL after corticotropin (nonresponders) defined adrenal reserve insufficiency. Response status was compared in the three outcome groups: survival with full neurologic recovery (n = 4), early death from refractory shock (n = 10), or later death from neurologic dysfunction (n = 19). Patients who died of early refractory shock had lower baseline cortisol levels than patients who died of neurologic dysfunction (27 microg/dL [15-47] vs. 52 microg/dL [28-73], respectively; P < 0.01), suggesting an inadequate adrenal response to severe systemic inflammation. Corticotropin response status was not associated with standard severity markers and seemed uninfluenced by therapeutic hypothermia. In conclusion, patients who die of early refractory shock after cardiopulmonary resuscitation may have an inadequate adrenal response to the stress associated with this condition. Thresholds for cortisol levels at baseline and after corticotropin need to be determined in this clinical setting.