Band 40, Heft 3

Zusammenfassung Derzeit sind über 400 medizinische Laboratorien in Deutschland nach der Norm DIN EN ISO 15189 (Medizinische Laboratorien – Anforderungen an die Qualität und Kompetenz) akkreditiert. Diese in der deutschen und novellierten Fassung im Jahr 2014 publizierte Norm enthält horizontal übergreifende, d. h. für alle Bereiche der medizinischen Laboratoriumsdiagnostik relevante Anforderungen, jedoch keine spezifischen Kriterien für die einzelnen Fachdisziplinen. In der vorliegenden Arbeit wurde untersucht, welchen Einfluss die Umsetzung der technischen Anforderungen der DIN EN ISO 15189, insbesondere der Anforderungen zu Untersuchungsverfahren und zur Qualitätssicherung, auf die Ergebnissicherheit in der Virusdiagnostik hat. Zum Vergleich wurden für die in dieser Arbeit dargelegte Studie innerhalb Deutschlands Experten aus klinisch-virologischen Instituten, Vertreter der In-Vitro-Diagnostika-Industrie, Vertreter der Deutschen Akkreditierungsstelle (DAkkS) sowie der Normung befragt. Aus der qualitativen Inhaltsanalyse der Interviews ergab sich, dass durch die Umsetzung der Anforderungen die Ergebnissicherheit erhöht und damit Risiken für die Patientenversorgung minimiert werden. Des Weiteren beschäftigte sich die Studie damit, welchen Einfluss die gemäß DIN EN ISO 15189 empfohlenen Qualitätskontrollen auf die Ergebnissicherheit im HIV-Combo-Test und im Anti-HBs-Nachweis haben. Die normativ empfohlenen, zusätzlichen Kontrollen („Run-Kontrollen“) offenbarten Insuffizienzen in der HIV-Antigenmessung, die durch Herstellerkontrollen nicht aufgedeckt wurden. In den vorgegebenen Bereichen befindliche Ergebnisse von testinternen Kontrollen garantierten nicht durchgängig korrekte Untersuchungsergebnisse, was am Beispiel der Anti-HBs-Bestimmung dargestellt wird. Schlussfolgernd wirkt sich die Anwendung der DIN EN ISO 15189, in der Regel bestätigt durch eine Akkreditierung, positiv auf die Ergebnissicherheit in der Virusdiagnostik und damit auch positiv auf die Patientenversorgung aus.

Background: The prognostic relevance of blood markers in multiple trauma is still a matter of controversial debate. Besides clinical scores new biomarkers indicating the disease severity and the prognosis during the first hours of therapy are highly needed to improve individual patient management. Methods: In prospectively collected sera of 164 patients, among them 115 with multiple trauma, the values of circulating nucleosomes, high-mobility-group-box protein 1 (HMGB1) and soluble receptor of advanced glycation end products (sRAGE) were determined at time of admission to the resuscitation room. Disease severity and clinical status were quantified by injury severity score (ISS) and Glasgow Coma Scale (GCS). As controls, 24 patients with femoral neck fractures and 25 patients with ankle fractures (AFs) were included. Results: Patients with severe multiple trauma (SMT) showed significantly higher HMGB1 and sRAGE levels than patients with moderate trauma and single fractures. Interestingly, HMGB1 and nucleosomes (R=0.56; p<0.01) as well as HMGB1 and sRAGE (R=0.44; p<0.01) correlated significantly with each other. In multiple trauma patients, high HMGB1 and sRAGE levels were significantly associated with more severe trauma according ISS (both p<0.01) and more severe traumatic brain injury (TBI) (GCS≤8; both p<0.01). Thirteen of the multiple injured patients died during the first week after trauma. Non-surviving patients showed significantly higher values of HMGB1, nucleosomes, and sRAGE than survivors (p<0.01; p=0.01; p=0.02). Best prediction of first-week mortality was obtained in receiver operating characteristic (ROC) curves for HMGB1 that yielded an area under the curve (AUC) of 90.6%. Conclusions: HMGB1, nucleosomes and sRAGE are valuable biomarkers indicating trauma severity and prognosis of trauma patients.

Background: Immediate treatment of lower respiratory tract infections (LRTI) caused by bacteria is important to reduce pneumonia and other complications such as systemic inflammatory response syndrome and sepsis. Nowadays procalcitonin (PCT) is the gold standard to differentiate between bacterial and non-bacterial infections in LRTI. The aim of this study was to evaluate if the new Intensive Care Infection Score (ICIS) which is a combination of various cellular measurements made on hematology analyzers could be a potential method to differentiate between bacterial and non-bacterial infections in LRTI. Methods: The ICIS is composed of five blood-cell derived parameters characterizing the early innate immune response; (1) mean fluorescence intensity of mature (segmented) neutrophils; (2) the difference in hemoglobin concentration between newly formed red blood cells and the mature ones; (3) absolute number of segmented neutrophils; (4) absolute count of antibody secreting lymphocytes and (5) absolute count of number of granulocytes. Results: The discriminative power of ICIS to differentiate between patients with LRTI of bacterial and non-bacterial origin is as good or even better as the commonly used infection biomarkers PCT, CRP and IL-6. Conclusions: Beside PCT, CRP and IL-6, ICIS could be used as infection marker in LRTI.

Background: Matrix-assisted laser desorption/ionization time-of flight mass spectrometry (MALDI-TOF MS) is a quick, reliable, and efficient system for identifying microorganisms. Many centers that use the Phoenix 100 system today may adopt a MALDI-TOF MS system in the future. Our laboratory recently undertook this pivot. The present study evaluates the reproducibility of species identifications made by the Phoenix 100 and MALDI-TOF MS systems, during a period of transitioning laboratory instrumentation. Methods: Eight hundred and twelve microbial isolates, from aerobic cultures of different clinical samples, were identified simultaneously with Phoenix 100 (Becton Dickinson, Sparks, MD, USA) and a Microflex LT MALDI-TOF MS (Bruker Daltonics, Bremen, Germany) devices. Results: Both systems made identical species assignments for 98.9%, 92.1%, 95.1%, and 93.1% of Gram-negative isolates, catalase-positive Gram-positive cocci isolates, catalase-negative Gram-positive cocci isolates, and Candida isolates, respectively. Conclusions: Identifications made by two instruments commonly used in microbiology laboratories, the Phoenix 100 and the Microflex LT MALDI-TOF MS, are highly consistent.

Zusammenfassung: Die Liquorzytologie ist eine technisch vergleichsweise einfache, dabei aber diagnostisch aussagefähige, schnell durchzuführende und kostengünstige Untersuchung, die auch im Rahmen des Notfall- und Basisprogramms der Liquordiagnostik nicht fehlen sollte. Die korrekte Durchführung und Interpretation setzt allerdings einige Erfahrung voraus. Anhand ausgewählter Beispiele zu den Themen Blutung, Meningitis und Meningeosis wird die Wertigkeit der Zytologie demonstriert, die oftmals nicht nur eine Ergänzung zu den üblichen quantitativen Bestimmungen ist, sondern nicht selten auch erst den diagnostisch entscheidenden Hinweis auf die zugrundliegende Erkrankung liefert: Bei der Subarachnoidalblutung ist sie hinsichtlich der Sensitivität der kranialen Computertomographie oftmals überlegen. Bei einer parasitären Meningitis liefert sie aufgrund des Nachweises eosinophiler Granulozyten erst die wesentliche Differentialdiagnose. Auch hinter einer normalen Zellzahl verbirgt sich gelegentlich eine Meningeois neoplastica. Tumorzellen lassen sich dabei mit Hilfe der Immunzytologie näher zuordnen. Entscheidend für eine aussagekräftige Zytologie ist allerdings die strikte Einhaltung präanalytischer Anforderungen.

Abstract: Reference limits need to be compared with each other for two main purposes: to evaluate the clinical relevance of a possible difference, if limits are obtained from the same population but at different time periods, or to check if limits derived from two different subpopulations can be considered as identical. The comparison of reference limits required for the periodic reviewing of applied reference limits and for checking the transferability of reference limits adopted from external sources according to international standards is an example for the first case. In the second case, a decision is intended whether the full population has to be partitioned (stratified) into the subpopulations under consideration (e.g. males and females). In both situations, differences may be due either to analytical errors, to biological differences or to both effects. The difference between reference limits may be acceptable if it is within permissible limits. For establishing permissible limits, the concept of equivalence limits was adopted to assess the relevance of differences between two reference limits. The concept bases on the permissible uncertainty at a particular reference limit. The permissible uncertainty is quantified by the permissible analytical standard deviation derived from the empirical biological variation as recently proposed. It is defined separately for lower and upper reference limits. The concept proposed can be condensed to simple equations.

Background: The objective of this study was to determine whether there is an association between successful uvulopalatopharyngoplasty (UPPP) and serum uric acid in patients with obstructive sleep apnea (OSA), and identify the risk markers for successful UPPP in OSA patients. Methods: We performed a prospective cohort study of 73 adult patients with OSA who underwent surgery (nasal or UPPP) at a major, urban, academic hospital in Huaian from 2011 to 2014 who had preoperative and postoperative clinical and laboratory profiles. Demographic, clinical, laboratory, and PSG parameters were carefully recorded. Logistic regression was used for the multivariate analysis of independent risk factors. Results: Changes of uric acid (UA), changes of C-reactive protein (CRP), changes of triglyceride, changes of high density lipoprotein before and after UPPP were significantly higher in OSA patients with successful UPPP than in those with unsuccessful UPPP (p<0.05). Among these patients, multiple logistic analyses indicated the independent risk factors for successful UPPP in the OSA subjects included changes of UA and CRP before and after UPPP. The diagnosis analysis showed that changes of UA and CRP before and after UPPP had a significant ability to reflect UPPP success in the OSA patients. Conclusions: The novel finding of this study is that the successful UPPP in OSA patients is strongly related to changes of serum UA level, CRP before and after operation. These results might be helpful for providing valuable information to reflect the effect of UPPP operation, regardless of UA and CRP before operation.

Background : The correlation between allergic diseases and migraine is partially due to a better understanding of inflammatory mediators with vasoactive function that play an important role in these diseases. This study aimed to evaluate the correlation between allergic sensitization and severity of migraine. Methods : This study was carried out on 212 patients who suffered from migraine headache in a university hospital in Mashhad, Iran. All of these patients were evaluated for allergic rhinitis (AR) by measuring the IgE level in peripheral blood and assessing the clinical symptoms of AR. Prevalence of AR in migraine patients and degree of allergic sensitization was assessed in this study. Results : The prevalence of AR in migraine patients was 78.30%. Total IgE levels in the peripheral blood in migraine patients with AR were found to be significantly (p<0.0001) higher than those without migraines. There was a significant difference between severity of AR (higher level of IgE) and severity of migraine attacks (p<0.0001), but there was not any significant difference between severity of AR and other factors. Conclusions : We propose that inflammatory mediators play a key role in triggering migraine attacks. Thus, effective treatment of AR in migraine patients plays an important role in treatment and prevention of migraine headaches.

Background: The demand for routine measurement of ferritin is constantly increasing in clinical laboratories due to the clinical value of this biomarker for diagnosing anemia. Therefore, this study was aimed to compare the newly commercialized Maglumi ferritin immunoluminometric assay with a validated commercial and fully automated technique. Methods: The comparison study included 95 consecutive inpatient serum samples referred to the local laboratory for routine ferritin measurement. Serum was separated, divided in two paired aliquots and immediately analyzed with both Beckman Coulter DxI 800 and Maglumi 2000. Correlation was assessed with Deming fit and Spearman’s correlation, the mean bias was estimated with Bland-Altman plot. The concordance between methods was calculated as percentage agreement and κ coefficient. Results: An excellent correlation was observed between Maglumi and DxI (r=0.997). The mean bias was 34 ng/mL and the strength of agreement between values obtained with Maglumi and DxI was 98% and 100% at the lower and upper limits of the reference range. The agreement was also 98% for diagnosing iron deficiency and 94% for diagnosing iron overload. Conclusions: Maglumi immunoassay may be regarded as a suitable alternative for routine and fully-automated assessment of ferritin in clinical laboratories.