Audit of sweat chloride testing reveals analytical errors.

OBJECTIVES: Sweat chloride testing (SCT) is the mainstay for the diagnosis of cystic fibrosis (CF) and biomarker in the evaluation of CFTR-modifying drugs. To be a reliable and valid tool, analytical variance (CVA) must be minimized. However, external quality assessments have revealed significant deviations in routine clinical practice. Our goal was to identify and quantify technical errors through proficiency testing and simulations. METHODS: Chloride concentrations of three blinded samples (each as triplicates) were measured in 9 CF centers using a chloridometer in a routine setting. Technical errors were simulated and quantified in a series of measurements. We compared imprecision and bias before and after a counseling session by evaluating coefficients of variation (CV), adherence to tolerance limits, and inter-rater variability coefficients. RESULTS: Pipetting errors resulting in changes in sample volume were identified as the main source of error with deviations up to 41%. After the counseling session, the overall CVA decreased from 7.6 to 5.2%, the pass rate increased from 67 to 92%, and the inter-rater variability diminished. Significant deviations continued to be observed in individual centers. CONCLUSIONS: Prevention of technical errors in SCT decreases imprecision and bias. Quality assurance programs must be established in all CF centers, including staff training, standard operating procedures, and proficiency testing.

Inhalation Devices in 7- to 15-Year-Old Children with Asthma - A Patient Preference Study.

Background: Inhalation therapy is the cornerstone of treatment of bronchial asthma. A patient-specific selection of inhalation devices is necessary, as preference for a device plays an important role in terms of error rates in handling and adherence to therapy. However, there is no industry-independent study providing information on children's preferences for common inhaler types. The aim of the present study was to investigate the preference of asthmatic children for inhaler types commonly used in Germany. The effects of age, gender and the type of school visited on device preferences as well as the frequency of patient education and the role of health care providers in the choice for an inhaler were investigated. Methods: Eighty children were included in this prospective cross-sectional study (age: 10.87 ± 2.62 years). The analysis was based on a questionnaire and validated checklists. All participants tested the use of nine placebo inhalers (Breezhaler, Diskus, Respimat, Spiromax, Turbohaler, Autohaler, metered-dose inhaler, Easyhaler and Novolizer) in a randomized order. For each device, patients were asked to assess handling, rate different device characteristics and name the device they would prefer most or least. Results: The most favored device was the Novolizer. Moreover, the Spiromax scored highest in numerous categories such as suitability in emergencies and "easiest" device to use. Patient preferences with respect to the addressed inhaler features were not significantly related to age, gender or school type. Conclusion: The Novolizer and the Spiromax showed higher preference in pediatric patients as compared to other tested devices. Overall, there were significant differences in terms of preference when comparing the tested inhalers in different aspects.

Increased blood plasma concentrations of TGF-beta1 and TGF-beta2 after treatment with intravenous immunoglobulins in childhood autoimmune diseases.

Transforming growth factor-beta (TGF-beta), a multifunctional, immunosuppressive cytokine, is shown to be present in substantial amounts in commercially available intravenous immunoglobulin (IVIG) preparations. To assess whether TGF-beta isoforms are changed in the plasma of paediatric patients with childhood autoimmune diseases after IVIG infusion, 17 patients who received over a period of 12 months overall 56 IVIG infusions (Endobulin) were enrolled in a study. High levels of TGF-beta1 (16.95 +/- 8.16 ng/ml) as well as TGF-beta2 (62.71 +/- 9.50 ng/ml) were detected in the used 56 IVIG probes. TGF-beta1 and TGF-beta2 plasma concentrations were measured prior and 120 min after IVIG infusions by specific TGF-beta ELISA. Interestingly, significant increased TGF-beta1 and TGF-beta2 plasma levels were found in patients after treatment with IVIG. This data suggest that a TGF-beta-mediated mechanism of action may accompany other molecular effects of IVIG therapy. The amount of the potent anti-inflammatory TGF-beta isoforms within the IVIG preparations may exert a differentiated view regarding the manifold indications of IVIG therapy.