Preoperative risk factors including serum levels of potassium, sodium, and creatinine for early mortality after open abdominal surgery: a retrospective cohort study.

BACKGROUND: In hospitalized patients, abnormal plasma electrolyte concentrations are frequent and have been linked to poor outcomes following acute surgery. The aim of this study was to assess whether preoperative plasma levels of potassium, sodium, and creatinine at the time of admission were associated with 30-day mortality in patients following open abdominal surgery. METHODS: This was a single-center register-based retrospective study. By means of electronic search in a maintained surgery database, all patients (n = 4177) aged ≥ 60 years old undergoing open surgery in our department from January 2000 to May 2013 were identified. Plasma was assessed within 30 days prior to surgery. The primary endpoint was 30-day postoperative mortality. The association between mortality and plasma levels of potassium, sodium, and creatinine were examined using Cox proportional hazard models. RESULTS: A total of 3690 patients were included in the study cohort. The rates of abnormal preoperative plasma levels were 36, 41, and 38% for potassium, sodium, and creatinine, respectively. The overall 30 day mortality was 20%. A predictive algorithm for 30 day mortality following abdominal surgery was constructed by means of logistic regression showing excellent distinction between patients with and without a fatal postoperative outcome. CONCLUSION: Apart from demographic factors (age, sex, and emergency surgery), preoperative imbalance in potassium, sodium and creatinine levels were significant independent predictors of early mortality following open abdominal surgery.

The microINR portable coagulometer: analytical quality and user-friendliness of a PT (INR) point-of-care instrument.

Regular measurement of prothrombin time as an international normalized ratio PT (INR) is mandatory for optimal and safe use of warfarin. Scandinavian evaluation of laboratory equipment for primary health care (SKUP) evaluated the microINR portable coagulometer (microINR®) (iLine Microsystems S.L., Spain) for measurement of PT (INR). Analytical quality and user-friendliness were evaluated under optimal conditions at an accredited hospital laboratory and at two primary health care centres (PHCCs). Patients were recruited at the outpatient clinic of the Laboratory of Medical Biochemistry, St Olav's University Hospital, Trondheim, Norway (n = 98) and from two PHCCs (n = 88). Venous blood samples were analyzed under optimal conditions on the STA-R®Evolution with STA-SPA + reagent (Stago, France) (Owren method), and the results were compared to capillary measurements on the microINR®. The imprecision of the microINR® was 6% (90% CI: 5.3-7.0%) and 6.3% (90% CI: 5.1-8.3) in the outpatient clinic and PHCC2, respectively for INR ≥2.5. The microINR® did not meet the SKUP quality requirement for imprecision ≤5.0%. For INR <2.5 at PHCC2 and at both levels in PHCC1, CV% was ≤5.0. The accuracy fulfilled the SKUP quality goal in both outpatient clinic and PHCCs. User-friendliness of the operation manual was rated as intermediate, defined by SKUP as neutral ratings assessed as neither good nor bad. Operation facilities was rated unsatisfactory, and time factors satisfactory. In conclusion, quality requirements for imprecision were not met. The SKUP criteria for accuracy was fulfilled both at the hospital and at the PHCCs. The user-friendliness was rated intermediate.

Comparison of the Quantum Blue® reader Point-of-Care system versus ELISA technique for therapeutic drug monitoring of Infliximab levels.

BACKGROUND: Infliximab (IFX) is a monoclonal antibody used to treat patients with inflammatory bowel disease (IBD). For IFX therapeutic drug monitoring (TDM), the most commonly used analysis is enzyme-linked immunosorbent assays (ELISA) which do not allow results to be provided in real-time. The aim of this study was to compare the in-house ELISA (Promonitor IFX) with the much faster assay Quantum Blue® IFX (QB) for quantification of serum IFX concentration among IBD patients in maintenance IFX therapy. METHODS: We studied 30 serum samples from outpatients in IFX maintenance therapy at Copenhagen University Hospital Hvidovre, Denmark. Samples were used to compare IFX measurements from Promonitor IFX with QB. Therapeutic intervals of <3 µg/mL, 3-7 µg/mL and >7 µg/mL were equally covered. Differences were evaluated using Bland-Altman plots and Student t-test. Correlation was evaluated using x,y-plot and Pearson's correlation coefficient. The intermediate imprecision (CV%) of QB was measured at two levels (3 µg/mL and 7 µg/mL). For qualitative comparison, weighted kappa statistics (κ) were determined after stratification of results by therapeutic interval. RESULTS: Promonitor IFX and QB were strongly correlated (r = 0.92, p < 0.001). The mean difference between Promonitor IFX and QB was -0.57 µg/mL (p = 0.2). The CV% of QB was 16.3% at 3 µg/mL and 16.7% at 7 µg/mL. Classification of results according to therapeutic interval showed almost perfect agreement (κ = 0.81). CONCLUSIONS: QB is a suitable alternative to Promonitor IFX for TDM in patients treated with IFX for IBD. The results revealed a strong correlation between methods, in particular at lower IFX concentrations, representing the most interesting clinical range. When the samples were stratified according to the therapeutic interval, an almost perfect agreement between the methods was observed.

EDTA-induced pseudothrombocytosis and citrate-induced platelet agglutination in a patient with Waldenstrom macroglobulinemia.

Hematology analyzers sometimes generate spurious results. A patient had EDTA-induced pseudothrombocytosis and platelet agglutination in citrate blood samples. This case verifies that addition of 1% paraformaldehyde to the citrate tubes can prevent platelet clumping. Further, it illustrates the advantages of having access to more than one platelet count method.

Reference intervals for C-peptide and insulin derived from a general adult Danish population.

BACKGROUND: Despite international efforts to standardize C-peptide and insulin calibrators and immunoassays, platform dependent differences still exist, and platform specific reference intervals are hence needed for correct interpretation. We therefore wanted to establish traceable reference intervals for C-peptide and insulin. METHODS: In 623 consecutively recruited participants, insulin and C-peptide were measured using the Cobas e411 (Roche Diagnostics, Switzerland). Participants with diabetes were excluded (fasting Glucose ≥7.0mmol/L or HbA1c≥6.5%/≥48mmol/L) and reference intervals were calculated with and without the inclusion of persons who were prediabetic, according to two definitions (The World Health Organization (WHO) and American Diabetes Association (ADA)). To ensure the correctness of calibration, the control pools were analyzed by a reference laboratory. The reference intervals were calculated according to the IFCC guidelines, using the RefVal software (Solberg, Oslo, Norway). RESULTS: Comparison of our results with those from the reference laboratory revealed equivalence for C-peptide results whereas the insulin determined on the Cobas e411 assay were 15-20% higher. The difference is attributed to an incorrect conversion factor for converting from activity to metric units. The Cobas e411 assay uses the factor 6.945 for converting from U/mL to pmol/L. This is in disagreement with the biological activity of insulin which is 166.8×106IU/mol or 6.00nmol/IU. CONCLUSION: We successfully established reference intervals for C-peptide and insulin for non-diabetic and prediabetic participants. The reference intervals for fasting C-peptide and fasting insulin are ready for implementation. A recertification of the insulin standards is needed.

Post-analytical stability of 23 common chemistry and immunochemistry analytes in incurred samples.

BACKGROUND: Storage of blood samples after centrifugation, decapping and initial sampling allows ordering of additional blood tests. The pre-analytic stability of biochemistry and immunochemistry analytes has been studied in detail, but little is known about the post-analytical stability in incurred samples. METHODS: We examined the stability of 23 routine analytes on the Dimension Vista® (Siemens Healthineers, Denmark): 42-60 routine samples in lithium-heparin gel tubes (Vacutainer, BD, USA) were centrifuged at 3000×g for 10min. Immediately after centrifugation, initial concentration of analytes were measured in duplicate (t=0). The tubes were stored decapped at room temperature and re-analyzed after 2, 4, 6, 8 and 10h in singletons. The concentration from reanalysis were normalized to initial concentration (t=0). Internal acceptance criteria for bias and total error were used to determine stability of each analyte. Additionally, evaporation from the decapped blood collection tubes and the residual platelet count in the plasma after centrifugation were quantified. RESULTS AND CONCLUSION: We report a post-analytical stability of most routine analytes of ≥8h and do therefore - with few exceptions - suggest a standard 8hour-time limit for reordering and reanalysis of analytes in incurred samples.

Apixaban used for the management of heparin-induced thrombocytopenia in a 72-year-old woman with lung cancer.

Heparin-induced thrombocytopenia (HIT) is a serious adverse reaction to heparin treatment with a high risk of thrombosis. Heparin must be discontinued immediately and replaced with alternative anticoagulants that do not interact with HIT antibodies. In this case, a lung cancer patient, diagnosed with HIT was successfully treated with apixaban.

A systematic review of trastuzumab and lapatinib in the treatment of women with brain metastases from HER2-positive breast cancer.

Patients with HER2-positive breast cancer are living still longer and increasingly experiencing brain metastases. Current HER2-targeted therapies have limited potential to cross the blood-brain-barrier. We performed a systematic review to investigate data on HER2-targeting therapies in the treatment of brain metastases in breast cancer. We searched PUBMED for all human studies published 1998-2012 using the following search terms: breast neoplasm/cancer, human epidermal growth factor receptor 2/HER2, ErbB2, trastuzumab, lapatinib, brain/cerebral neoplasm/metastases and blood-brain barrier. We identified few and mostly small clinical studies. Study designs were very heterogeneous making comparisons on endpoints difficult. Overall survival for patients treated with trastuzumab varied from 8 to 25 months and 5.5 to 11 months for patients receiving lapatinib. The majority of studies were retrospective thus possibly biasing data. Only three studies were identified comparing trastuzumab to lapatinib. Conclusively, no solid data exist on how to treat patients with HER2-positive disease and brain metastases. Although continuous HER2-blockade is recommended by international consensus guidelines, it is still not evident which HER2-targeting agent should be preferred when brain metastases occur. The choice of chemotherapy to accompany the blockade is not obvious and we do not know if dual is better than single blockade. Further clinical trials are urgently needed.