Comparison of HbA1c Measurements using 3 Methods in 75 Patients Referred to One Outpatient Department.

OBJECTIVE: HbA1c is the most important surrogate parameter to assess the quality of diabetes care and is also used for the diagnosis of diabetes mellitus (DM) since 2010. We investigated the comparability of 3 HbA1c methods in the city of Jena (Germany). METHODS: The HbA1c determination was carried out in 50 healthy subjects and 24 people with DM (age 51.2±16.3 years, HbA1c 6.8±2.2%) with 3 different hemoglobin A1c testing methods at 4 locations in one city. Our laboratory (HPLC method) served as a reference for comparing the results. All methods are IFCC standardized and all devices are certified by the interlaboratory test. RESULTS: The mean HbA1c of people without diabetes was: laboratory A (TOSOH G8, HPLC) 5.7±0.3%; laboratory B (TOSOH G8, HPLC) 5.5±0.3%, laboratory C (VARIANT II) 5.2±0.3%; laboratory D (COBAS INT.) 5.6±0.3%. All differences are significant (p=0.001).The mean HbA1c of patients with mild to moderate elevated HbA1c was: Laboratory A 7.5±0.9%; B 7.3±1.0%; C 7.0±0.9%; D 7.5±1.1%. Differences are significant (p=0.001) except between laboratory A and D (p=0.8).The mean HbA1c of patients with massively increased HbA1c was: laboratory A 11.5±1.8%; laboratory B 11.4±1.8%; laboratory C 10.8±1.6%; laboratory D 11.5±1.5%. Differences between laboratory A and C, as well as between C and D were significant (p=0.001). CONCLUSION: The mean IFCC standardized HbA1c from 75 people differs by up to 0.5% absolute between 4 laboratories. This difference is clinically significant and may lead to misdiagnosis and wrong treatment decisions, while HbA1c value from one patient were analyzed in different laboratories within a short time.

A severe pediatric infection with a novel enterovirus A71 strain, Thuringia, Germany.

Infection by Enterovirus A71 (EV-A71) is an important cause of hand, foot, and mouth disease (HFMD). Outbreaks including severe cases with neurological and cardiopulmonary complications have been reported particularly from Southeast Asia. In Europe, the epidemiology of EV-A71 is not well understood. In summer 2015, a two-year-old girl from Thuringia, Germany, presented with rhombencephalitis/brainstem encephalitis associated with severe neurological and cardiopulmonary complications. EV-A71 was detected in stool and almost the entire viral genome was amplified and sequenced. While the capsid protein VP1-encoding region belongs to the EV-A71 subgenogroup C1, the 3D polymerase encoding region represents a unique lineage. Thus, the data suggest that the Thuringian EV-A71 sequence likely represents a recombinant. The case underlines the importance of intensified EV-A71 surveillance in Germany and Europe including analysis of full-genome data.

Colonization of CF patients' upper airways with S. aureus contributes more decisively to upper airway inflammation than P. aeruginosa.

In cystic fibrosis (CF) patients' airways, inflammatory processes decisively contribute to remodeling and pulmonary destruction. The aims of this study were to compare upper airway (UAW) inflammation in the context of Staphylococcus aureus and Pseudomonas aeruginosa colonization in a longitudinal setting, and to examine further factors influencing UAW inflammation. Therefore, we analyzed soluble inflammatory mediators in noninvasively obtained nasal lavage (NL) of CF patients together with microbiology, medication, and relevant clinical parameters. NL, applying 10 mL of isotonic saline per nostril, was serially performed in 74 CF patients (326 samples). Concentrations of the inflammatory mediators' interleukin (IL)-1ß, IL-6, IL-8, matrix metalloproteinase (MMP)-9, and its anti-protease TIMP-1 were quantified by bead-based multiplexed assay, neutrophil elastase (NE) via ELISA. Culture-based microbiology of the upper and lower airways (LAW), as well as serological and clinical findings, were compiled. Our results indicate that UAW colonization with S. aureus significantly impacts the concentration of all measured inflammatory mediators in NL fluid except TIMP-1, whereas these effects were not significant for P. aeruginosa. Patients with S. aureus colonization of both the UAW and LAW showed significantly increased concentrations of IL-1ß, IL-6, IL-8, MMP-9, and slightly elevated concentrations of NE in NL fluid compared to non-colonized patients. This work elaborates a survey on S. aureus' virulence factors that may contribute to this underestimated pathology. Serial assessment of epithelial lining fluid by NL reveals that colonization of the UAW with S. aureus contributes more to CF airway inflammatory processes than hitherto expected.

Reduced effect of intravenous antibiotic treatment on sinonasal markers in pulmonary inflammation.

BACKGROUND: Chronic bacterial rhinosinusitis is a common feature in Cystic fibrosis (CF) as mucociliary clearance in the sinonasal compartment is impaired. Aim of the present prospective study was to compare dynamics of inflammatory markers in the upper and lower airways (UAW/LAW) during systemic antibiotic therapy. METHODS: Nasal lavage and sputum of 16 CF-patients receiving an IV-antibiotic treatment against Pseudomonas aeruginosa and/ or Staphylococcus aureus were collected before and during treatment (median after 7.5 days). Cytological changes, DNA concentration, and inflammatory markers interleukin (IL)-4, IL-8, IL-13 and Myeloperoxidase (MPO) were assessed in samples from both airway compartments. RESULTS: Total cell count declined significantly in LAW-samples but not in UAW. Although MPO and IL-8 decreased significantly in both airway compartments, this was considerably more pronounced for LAW (median decrease MPO: LAW=9.8-fold vs UAW=1.75-fold, respectively; IL-8: LAW=3-fold vs UAW=1.9-fold, respectively). DISCUSSION: This is the first publication demonstrating substantially lower effects of IV-antibiotic treatment on sinonasal than on pulmonary inflammatory markers. Consequently, our findings highlight limitations of systemic antibiotic treatment to control infection in the sinonasal compartment. Primarily, we attribute this to the paranasal sinus ́ structure: these hollow organs, which in bacterial sinusitis are frequently filled with pus, mucoeceles and polyps, are not reached effectively by systemic antibiotic treatment.

Changes of Proteases, Antiproteases, and Pathogens in Cystic Fibrosis Patients' Upper and Lower Airways after IV-Antibiotic Therapy.

BACKGROUND: In cystic fibrosis (CF) the upper (UAW) and lower airways (LAW) are reservoirs for pathogens like Pseudomonas aeruginosa. The consecutive hosts' release of proteolytic enzymes contributes to inflammation and progressive pulmonary destruction. Objectives were to assess dynamics of protease : antiprotease ratios and pathogens in CF-UAW and LAW sampled by nasal lavage (NL) and sputum before and after intravenous- (IV-) antibiotic therapy. METHODS: From 19 IV-antibiotic courses of 17 CF patients NL (10 mL/nostril) and sputum were collected before and after treatment. Microbiological colonization and concentrations of NE/SLPI/CTSS (ELISA) and MMP-9/TIMP-1 (multiplex bead array) were determined. Additionally, changes of sinonasal symptoms were assessed (SNOT-20). RESULTS: IV-antibiotic treatment had more pronounced effects on inflammatory markers in LAW, whereas trends to decrease were also found in UAW. Ratios of MMP-9/TIMP-1 were higher in sputum, and ratios of NE/SLPI were higher in NL. Remarkably, NE/SLPI ratio was 10-fold higher in NL compared to healthy controls. SNOT-20 scores decreased significantly during therapy (P = 0.001). CONCLUSION: For the first time, changes in microbiological patterns in UAW and LAW after IV-antibiotic treatments were assessed, together with changes of protease/antiprotease imbalances. Delayed responses of proteases and antiproteases to IV-antibiotic therapy were found in UAW compared to LAW.

Protease-antiprotease imbalances differ between Cystic Fibrosis patients' upper and lower airway secretions.

BACKGROUND: Balanced levels of proteases and anti-proteases are essential in host defense systems. In CF patients' lungs, elevated protease/anti-protease-ratios contribute to damage of airway tissue and premature death with the inherited disease. Little is known about upper airway protease equilibrium in CF. METHODS: Neutrophil elastase (NE), Secretory leukocyte protease inhibitor (SLPI), matrix metalloproteinase (MMP)9, tissue inhibitors of metalloproteinase (TIMP)1, cathepsin S (CTSS) and the corresponding cellular distribution were assessed in the nasal lavage (NL) and sputum of 40 CF patients. RESULTS: Concentrations of all proteases and anti-proteases were markedly higher in sputum than in NL (NE: 10-fold, SLPI: 5000-fold). Interestingly, the NE/SLPI ratio was 726-fold higher in NL compared to sputum, while the MMP9/TIMP1 ratio was 4.5-fold higher in sputum compared to NL. DISCUSSION: This first study to compare protease/anti-protease networks of CF upper and lower airways by NL and sputum reveals substantial differences between both compartments' immunological responses. This finding may have implications for sinonasal and pulmonary treatment, possibly leading to new therapeutic approaches.

Dynamics of soluble and cellular inflammatory markers in nasal lavage obtained from cystic fibrosis patients during intravenous antibiotic treatment.

BACKGROUND: In cystic fibrosis (CF) patients, the upper airways display the same ion channel defect as evident in the lungs, resulting in chronic inflammation and infection. Recognition of the sinonasal area as a site of first and persistent infection with pathogens, such as Pseudomonas aeruginosa, reinforces the "one-airway" hypothesis. Therefore, we assessed the effect of systemic antibiotics against pulmonary pathogens on sinonasal inflammation. METHODS: Nasal lavage fluid (NLF) from 17 CF patients was longitudinally collected prior to and during elective intravenous (i.v.) antibiotic treatment to reduce pathogen burden and resulting inflammation (median treatment time at time of analysis: 6 days). Samples were assessed microbiologically and cytologically. Cytokine and chemokine expression was measured by Cytometric Bead Array and ELISA (interleukin (IL)-1ß, IL-6, IL-8, MPO, MMP9, RANTES and NE). Findings were compared with inflammatory markers from NLF obtained from 52 healthy controls. RESULTS: Initially, the total cell count of the NLF was significantly higher in CF patients than in controls. However after i.v. antibiotic treatment it decreased to a normal level. Compared with controls, detection frequencies and absolute concentrations of MPO, IL-8, IL-6 and IL-1ß were also significantly higher in CF patients. The detection frequency of TNF was also higher. Furthermore, during i.v. therapy sinonasal concentrations of IL-6 decreased significantly (P = 0.0059), while RANTES and MMP9 levels decreased 10-fold and two-fold, respectively. PMN-Elastase, assessed for the first time in NFL, did not change during therapy. CONCLUSIONS: Analysis of NLF inflammatory markers revealed considerable differences between controls and CF patients, with significant changes during systemic i.v. AB treatment within just 6 days. Thus, our data support further investigation into the collection of samples from the epithelial surface of the upper airways by nasal lavage as a potential diagnostic and research tool.

Influences of nasal lavage collection-, processing- and storage methods on inflammatory markers--evaluation of a method for non-invasive sampling of epithelial lining fluid in cystic fibrosis and other respiratory diseases.

BACKGROUND: Non-invasive sampling of airway epithelial-lining-fluid by nasal lavage (NL) is an emerging method to monitor allergy, infection and inflammation in patients with respiratory diseases. However, the influences of collection-, processing- and storage-methods have not been sufficiently evaluated and standardized. METHODS: Influences of repeated NL, centrifugation setups, repeated freezing and thawing, and protease inhibitors on mediator concentration were evaluated in healthy controls and CF patients, which serve as a model for chronic bacterial infection and inflammation. Polymorphonuclear leukocyte elastase (NE)/myeloperoxidase (MPO)/interleukin (IL)-1/IL-6/IL-8 and tumour necrosis factor alpha (TNF) concentrations were measured using ELISA and Multiplex Bead-Arrays. RESULTS: NL-repetition within 0.5-4h markedly decreased NE, IL-8 and MPO-concentrations for up to 70%. NL centrifugation up to 250×g for cellular differentiation did not significantly influence mediator concentration in native and processed NL fluid. NL freezing and thawing markedly decreased IL-8 and MPO concentrations by up to 50% while NE remained stable. In contrast to preceding reports, storing at -70°C for ≥5 years led to significantly reduced mediator concentrations in NL compared to contemporary analyses, being most pronounced for IL-1ß, IL-6 and TNFa. Storing of samples in the presence of protease inhibitors led to an increase in marker concentration for IL-8 (+27%) and MPO (+15%) even after one year of storage. CONCLUSIONS: NL is an easy and robust technique for inflammation monitoring of the upper airways. For the first time we have shown that diagnostic NL should be performed only once daily to get comparable results. Whereas NL-fluid can be stored unprocessed at -70°C for cytokine analysis over 1-2 years with protease inhibitors supporting stability, ≥5 years storage as well as repeated freezing and thawing should be avoided.

Isolated central nervous system relapse of chronic myeloid leukemia after allogeneic hematopoietic stem cell transplantation.

BACKGROUND: This case report highlights the relevance of quantifying the BCR-ABL gene in cerebrospinal fluid of patients with suspected relapse of chronic myeloid leukemia in the central nervous system. CASE PRESENTATION: We report on a female patient with isolated central nervous system relapse of chronic myeloid leukemia (CML) during peripheral remission after allogeneic hematopoietic stem cell transplantation. The patient showed a progressive cognitive decline as the main symptom. MRI revealed a hydrocephalus and an increase in cell count in the cerebrospinal fluid (CSF) with around 50% immature blasts in the differential count. A highly elevated BCR-ABL/ ABL ratio was detected in the CSF, whilst the ratio for peripheral blood and bone marrow was not altered. On treatment of the malresorptive hydrocephalus with shunt surgery, the patient showed an initial cognitive improvement, followed by a secondary deterioration. At this time, the cranial MRI showed leukemic infiltration of lateral ventricles walls. Hence, intrathecal administration of cytarabine, methotrexate, and dexamethasone was initiated, which caused a significant decrease of cells in the CSF. Soon after, the patient demonstrated significant cognitive improvement with a good participation in daily activities. At a later time point, after the patient had lost the major molecular response of CML, therapy with dasatinib was initiated. In a further follow-up, the patient was neurologically and hematologically stable. CONCLUSIONS: In patients with treated CML, the rare case of an isolated CNS blast crisis has to be taken into account if neurological symptoms evolve. The analysis of BCR-ABL in the CSF is a further option for the reliable detection of primary isolated relapse of CML in these patients.

Lactic acid is of low predictive value for the diagnosis of bacterial infection in ventricular cerebrospinal fluid samples containing residual blood.

BACKGROUND: Lactic acid concentrations (LA) are an established marker of bacterial infection in cerebrospinal fluid (CSF). However, use of LA for the detection of infection in CSF with residual blood has not been fully evaluated. METHODS: Analysis of LA and total protein, cell count and bacterial culture were performed in 90 lumbar and ventricular CSF samples contaminated with blood. RESULTS: Bacterial culture was positive in six CSF samples. The diagnostic value of the cell count was significantly higher than that of LA for the prediction of a positive culture, even if all culture positive and all likely infected samples were included in the analysis. There was no significant difference in LA concentrations between positive or likely positive ventricular CSF samples and all negative, ventricular samples. CONCLUSIONS: Although LA concentrations in CSF are evidently a predictor of bacterial infection, its diagnostic value for the detection of bacterial infection in ventricular CSF with residual blood is limited.

CD62L on neutrophil granulocytes, a useful, complementary marker for the prediction of ventriculitis in blood-containing CSF.

OBJECTIVES: Presence of residual blood is a common problem in cerebrospinal fluid (CSF) diagnostics of ventriculitis. We hypothesised that neutrophil granulocytes in infected, blood-containing CSF lose CD62L expression. Therefore CD62L expression on neutrophils may present a complementary marker to distinguish between patients with residual blood and infection. DESIGNS AND METHODS: Evaluation was performed in 64 ventricular CSF samples sent to the laboratory for diagnostic investigation. Cell count, microbiological culture, total protein and flow cytometric analysis of CSF were performed. RESULTS: Cell counts and CD62L expression were significantly different between the culture positive and negative group. ROC-analysis revealed a significant predictive value for cell count and CD62L expression. Optimal cut-offs were calculated and a decision tree was established to predict a positive culture. CONCLUSIONS: Cell count and CD62L expression were predictive for a positive culture and the combination helped to increase specificity and sensitivity for the detection of ventriculitis in blood-containing CSF.

Quantitation of serum free light chains does not compensate for serum immunofixation only when screening for monoclonal gammopathies.

BACKGROUND: Detection of plasma cell dyscrasias (PCD) requires screening of serum and urine for monoclonal proteins. Several studies have demonstrated increased sensitivity and specificity when measurement of serum free light chain (SFLC) is part of the screening protocol. In addition, omission of immunofixation (IFE) in the standard work-up that includes SFLC assay has been proposed. This study attempts to define the role of the SFLC assay in a screening strategy limited to serum only. It compares outcomes to a serum-only screening strategy that omits serum IFE. METHODS: Serum from 691 patients was analysed for the presence of monoclonal protein using standard serum IFE, serum protein electrophoresis (SPE) and measurement of SFLC. Data were analysed retrospectively. RESULTS: Specificity and sensitivity of abnormal SFLC-ratios for the detection of monoclonal protein using IFE were 96% and 41%, respectively. Eighteen patients with negative monospecific and Bence Jones IFE, but abnormal SFLC-ratios were identified. In most cases, this could be attributed to kidney and inflammatory disease or haematological disorders. In four cases, this resulted in further diagnostic investigation and light chain disease was later detected in two cases. Light chain disease was confirmed in one case but not confirmed in the other patient. In 14 patients, Bence Jones IFE was negative, although the concentrations of SFLC suggested the presence of monoclonal Bence Jones protein at concentrations detectable by IFE. Thus, either the anti-serum failed at detection, there was polymerisation of the free light chains or the SFLC assay overestimated protein concentrations. Simulating a work-up that included IFE only if abnormalities were detected by SPE or the SFLC assay would have resulted in 26% fewer IFEs being performed, but three patients with monoclonal proteins by IFE would have been missed. CONCLUSIONS: Abnormal SFLC concentrations are neither sensitive nor specific for the detection of monoclonal proteins by IFE. Not all PCD are accompanied by excessive production of SFLC, and several other conditions, such as renal disease are associated with increased SFLC concentrations. An abnormal SFLC-ratio is a specific marker for PCD, and occurs primarily in patients with haematological disease. If renal and inflammatory diseases are excluded, this should prompt further diagnostic investigation. Screening of serum without performing an IFE as a standard procedure leads to a reduction of sensitivity when compared to screening of serum that includes IFE.

Workflow restrictions on hematology analyzers XE-2100 and XS-800 when assaying pediatric samples with limited volume.

BACKGROUND: Samples with limited volume is a common problem in laboratories receiving samples from pediatric patients. Also, pediatric samples may contain nucleated red blood cells (NRBC) which distorts the white blood cell (WBC) count and which can only be measured by some automated cell counting systems. Differential counts are sometimes required, posing the question of validity of flagging depending on age of the patients and on predilutions. METHODS: We evaluated the hematology analyzers XE-2100 and XS-800 for their suitability in measuring hematological parameters in such samples. RESULTS: With the exception of the MCHC and partly the MCH, we observed very good agreement between complete blood counts (CBC) in diluted and undiluted samples. Dilution did not impair sensitivity in the clinically relevant range nor, accuracy of the NRBC count on XE-2100. Flagging was ineffective in undiluted samples from children<1 year of age and in all diluted samples when measuring differential counts. CONCLUSIONS: In summary, while automated measurement of CBC and NRBC is possible in diluted samples, measurement of differential counts is restricted by loss of flagging efficiency. In addition, flagging is also ineffective in children<1 year of age using the analyzers evaluated and should, for diagnostic purposes, be performed manually.

Evaluation of the XE-5000 for the automated analysis of blood cells in cerebrospinal fluid.

OBJECTIVES: Counting of cells in cerebrospinal fluid is an important clinical laboratory test and elevated white blood cell counts in cerebrospinal fluid are frequently seen in CNS disorders. Quantification of red blood cell concentrations in CSF may help to interpret certain diagnostic constellations and may result from subarachnoid haemorrhage, surgical procedures or contamination due to traumatic puncture. Table top analyser XE-5000 (Sysmex, Norderstedt, Germany) offers, beside its use as a haematology analyser, a protocol for the quantification of red and white blood cells in body fluids such as CSF including the differentiation between polymorphonuclear and mononuclear cells. A detection limit of 1 cell/mm(3) would render this device suitable for automated CSF analysis. DESIGN AND METHODS: White blood cell counting was compared between Fuchs-Rosenthal counting chamber and XE-5000 in 273 routinely collected lumbar and ventricular CSF samples. Red blood cell counting was compared between UF-100 and XE-5000. Differentiation was performed on a slide stained after Pappenheim and compared to the differential count of the XE-5000. RESULTS: Linearity was established between 1 and 10,000 cells/mm(3) for white blood cells and between 1000 and 110(3) particles/mm(3) for red blood cells. Functional sensitivity was established at 20 cells/mm(3) for white blood cell counting and at 1000 particles/mm(3) (lowest reported concentration) for red blood cell counting. When comparing between microscopic and automatic white blood cell counts no statistically significant slope and offset were detected in lumbar CSF samples while a significant slope and offset were detected when comparing ventricular CSF samples. Most patients were classified correctly according to their WBC count (non-pathologic, mildly, moderately, and highly elevated) by both methods although more patients had pathologic white blood cell counts on XE-5000. A significant slope and offset were detected when comparing red blood cell counts between UF-100 and XE-5000. CONCLUSIONS: In summary despite its high imprecision at low white blood cell counts (<20 particles/mm(3)) most patients were classified correctly and therefore XE-5000 is suitable for automated quantification of white blood cells in cerebrospinal fluid in a defined diagnostic setting. This could significantly improve automation in the relatively time- and manual work-intensive field of cerebrospinal fluid diagnostics. However, careful review of plausibility of the results continues to be compulsory.

Influence of direct thrombin inhibitor argatroban on coagulation assays in healthy individuals, patients under oral anticoagulation therapy and patients with liver dysfunction.

We assumed that argatroban, a direct thrombin inhibitor, has a strong influence on different coagulation tests which is even more pronounced in patients with an established reduced factor activity like those under oral anticoagulation therapy or with liver dysfunction. To validate this influence we spiked plasma samples from healthy individuals, patients under oral anticoagulation therapy or with liver dysfunction with increasing argatroban concentrations (0-2000 ng/ml) and performed routine laboratory coagulation tests. Consequently, prothrombin time, activated partial thromboplastin time, thrombin time, batroxobin time, coagulation factor activity (FII-FXIII), protein S (activity), protein C (chromogen) and fibrinogen (derived and Clauss fibrinogen method) were measured. Furthermore, the influence of argatroban on the induced platelet aggregation was evaluated. Argatroban interference on standard coagulation assays differed markedly depending on the different subgroups of patients investigated. Prolongation of prothrombin time by argatroban (at 2000 ng/ml 2.7-fold in healthy persons) was significantly higher in oral anticoagulation therapy (3.9-fold) and even more pronounced in liver dysfunction (6.0-fold). The fibrinogen concentration was determined falsely even at low-argatroban concentrations using functional methods in healthy persons and all patient subgroups. The influence of argatroban on standard laboratory coagulation tests is significantly increased by a preexisting factor deficiency. Functional fibrinogen measurement may be helpful to assess in-vivo fibrinogen function but should be avoided to evaluate fibrinogen concentration in argatroban treated patients. Argatroban had no influence on chromogenic protein C measurement, batroxobin time and induced platelet aggregation. Knowledge of argatroban interference is a prerequisite for the reliable interpretation of coagulation assays.

Comparison of the ecarin chromogenic assay and different aPTT assays for the measurement of argatroban concentrations in plasma from healthy individuals and from coagulation factor deficient patients.

INTRODUCTION: The aim of this study was to assess the usefulness of different aPTT assays and the ecarin chromogenic assay reaction time (ECA) for measurement of argatroban concentration in plasma from healthy persons as well as in different patient subgroups. METHODS: We spiked plasma samples from healthy individuals, patients under oral anticoagulation (OAT) or with liver dysfunction (LD) with increasing argatroban concentrations (0-2000 ng/ml) and performed 4 different aPTTs assays and the ECA. RESULTS: Depending on argatroban concentrations aPTTs increased in a curvilinear fashion; in plasma from healthy individuals means of calculated argatroban concentration at 2-fold aPTT differed extensively depending on the aPTT reagent used (725 ng/ml to 1136 ng/ml) and were even more pronounced in plasma from coagulation factor deficient patients (460 ng/ml in patients with LD vs. 1172 ng/ml in patients with OAT), whereas ECA showed linear argatroban influence and reliable results in all subgroups. CONCLUSIONS: Because of wide differences in aPTT measurements depending on the aPTT reagent used, interindividual variations and different clinical conditions the aPTT is not the method of choice for monitoring argatroban and the ECA should be preferred.

Automated monitoring of C2 and C0 blood levels of mycophenolic acid and cyclosporine on the Abbott Architect c8000.

OBJECTIVES: Evaluation of the performance of the EMIT 2000 Cyclosporin assay using 2 sets of assay calibrators and the EMIT 2000 mycophenolic acid assay to measure C0 and C2 concentrations on the Abbott Architect c8000 analyzer. DESIGN AND METHODS: Imprecision studies were performed. Cyclosporin concentration was assayed by EMIT on the c8000, by ACMIA on the Dimension and by LC-MS/MS while mycophenolic acid was analyzed by EMIT on c8000 and on Dimension and by HPLC. RESULTS: Agreement between cyclosporin and mycophenolic acid concentrations assayed on the c8000 and on the Dimension was very good. Method comparison between the c8000 and LC-MS/MS resulted in a relative bias of 15.7% for C0 and 11.5% for C2 concentrations. Relative bias of the mycophenolic acid concentrations assayed on the c8000 and the HPLC was 37.7%. CONCLUSIONS: When reported properly to the clinician mycophenolic acid and cyclosporine blood levels can be monitored using the EMIT assays on the c8000 consolidating standard routine workflow and reducing reagent costs significantly.

Strong interference of hemoglobin concentration on CSF total protein measurement using the trichloroacetic acid precipitation method.

BACKGROUND: Among other methods, trichloroacetic acid precipitation is used to quantify total protein in cerebrospinal fluid (CSF). METHODS: We analyzed the influence of hemoglobin on total protein concentration assayed by the trichloroacetic acid method and compared the results to the benzethonium chloride method. RESULTS: Four CSF samples were spiked with different amounts of hemoglobin, leading to overestimation of protein concentration when assayed by the trichloroacetic acid method. Using the benzethonium chloride method, measurement of protein concentration was minimally disturbed. In addition, albumin and total protein concentrations were measured in 135 clinical samples. The total protein/albumin ratio remained constant when protein was measured with the benzethonium chloride method, while ratios increased when protein was assayed by the trichloroacetic acid method. CONCLUSIONS: Strong interference by hemoglobin leads to overestimation of the total protein concentration in CSF when assayed by the trichloroacetic acid method and may lead to false conclusions when evaluating the blood-brain barrier.

Application of the EMIT 2000 Tacrolimus assay on the Abbott Architect c8000 high volume clinical chemistry analyzer.

OBJECTIVES: Evaluation of the performance of the EMIT 2000 Tacrolimus assay on the Abbott Architect c8000 analyzer. DESIGN AND METHODS: Imprecision studies were performed and patient samples were assayed by EMIT assay and by LC-MS/MS. RESULTS: Limit of quantification was established at 2.8 microg/L. A positive bias of 17.5% between results measured on EMIT and on LC-MS/MS was detected. CONCLUSIONS: EMIT 2000 Tacrolimus assay is suitable for automated analyses of Tacrolimus on the Architect c8000.