Synovial neutrophilic gelatinase-associated lipocalin in the diagnosis of periprosthetic joint infection after total knee arthroplasty.

BACKGROUND: Periprosthetic joint infection (PJI) is one of the most serious complications following total knee arthroplasty (TKA). However, the diagnosis remains a challenge for clinicians. In 2011, the muscoskeletal infection society (MSIS) criteria provided a consensus which has been updated in 2013, but these criteria are complex and contain tests that are time-consuming. The same is applicable to the pro-Implant guidelines. Therefore, a simpler diagnostic test is desirable. OBJECTIVES: The value of neutrophil gelatinase-associated lipocalin (NGAL), leucocyte esterase (LE) levels, and the white blood cell (WBC) count in synovial fluid to diagnose PJI after TKA was evaluated. METHODS: In a retrospective cohort study, we analyzed 89 synovial fluid samples from 86 patients with suspected PJI after TKA. Thirteen and 23 of those samples were classified as PJI according to the MSIS and pro-Implant criteria, respectively. Subsequently, NGAL, LE levels, and the WBC count were determined, the former one using an immunoassay. Using either the MSIS or pro-Implant criteria as the golden standard for PJI, sensitivity and specificity of those markers were determined with ROC curves, and medians were compared with Mann-Whitney U and Pearson Chi-square tests. RESULTS: When applying the MSIS criteria, NGAL revealed 92% sensitivity and 83% specificity. WBC count showed similar sensitivity (92%) and specificity (84%), whereas sensitivity and specificity for LE were 39% and 88% respectively. When applying the pro-Implant criteria, sensitivity was 95% and specificity was 95% for NGAL. Sensitivity and specificity for WBC count were 100% and 97% and for LE 39% and 92% respectively. CONCLUSION: NGAL and WBC count in synovial fluid has high accuracy in the diagnosis of PJI after TKA and should seriously be considered as part of PJI diagnostics. Leucocyte esterase can serve as rule-in criterion peroperatively. These conclusions are independent of which criteria set was used as golden standard.

Acute myeloid leukaemia: How to combine multiple tools.

The pathogenesis of acute myeloid leukaemias (AML) frequently requires at least 3 mutations in different cellular pathways. In many cases, mutations in proliferation/survival mechanisms and differentiation pathways are involved. Genetic aberrations explain the pathogenesis of AML, provide prognostic criteria and guide drug design for future therapy. Since the last update of the World Health Organization (WHO) classification of tumours of the hematopoietic and lymphoid tissues in 2008, there have been many discovers regarding the genomic landscape of AML and molecular assays for the detection of minimal residual disease. The identification of unique biomarkers associated with AML, derived from gene expression analysis and next-generation sequencing, may improve significantly the diagnostic criteria. In the new WHO classification published in 2017, several new AML entities are added. Moreover, the prognostic and diagnostic relevance of recently identified molecular features is reviewed and integrated into existing sets of criteria. This article reviews the most common tests and procedures for AML diagnosis, including morphology, immunophenotyping, cytogenetics and molecular genetic testing. The major changes in the new WHO classification for AML are also remarked.

Oral Tobramycin Prophylaxis Prior to Colorectal Surgery Is Not Associated with Systemic Uptake.

Preoperative oral prophylaxis with nonabsorbable antibiotics has been reported to reduce the risk of surgical site infections after colorectal surgery. This prospective study was conducted to evaluate the risk of toxic side effects by measuring postoperative serum tobramycin levels in patients who received a 3-day prophylaxis with tobramycin and colistin prior to colorectal surgery. In all patients, serum tobramycin concentrations were below the detection limit (0.3 mg/liter), implying a low risk of toxicity.

Recommendation for standardization of haematology reporting units used in the extended blood count.

INTRODUCTION: It is desirable in the interest of patient safety that the reporting of laboratory results should be standardized where no valid reason for diversity exists. This study considers the reporting units used for the extended blood cell count and makes a new ICSH recommendation to encourage standardization worldwide. METHODS: This work is based on a literature review that included the original ICSH recommendations and on data gathered from an international survey of current practice completed by 18 countries worldwide. RESULTS: The survey results show that significant diversity in the use of reporting units for the blood count exists worldwide. The use of either non-SI or other units not recommended by the ICSH in the early 1980s has persisted despite the guidance from that time. CONCLUSION: The diversity in use of reporting units occurs in three areas: the persistence in use of non-SI units for RBC, WBC and platelet counts, the use of three different units for haemoglobin concentration and the manual reporting of WBC differential, reticulocytes and nucleated RBCs when the latter are available from automated analysis or can be expressed as absolute numbers by calculation. A new recommendation with a rationale for each parameter is made for standardization of the reporting units used for the extended blood count.

[A neonate with umbilical cord bleeding]. / Een neonaat met een navelstompbloeding.

A 7-day-old neonate was admitted to our neonatal ward for umbilical stump bleeding. His medical history included hyperbilirubinaemia due to cephalic haematoma. Only after the administration of fresh frozen plasma, the bleeding stopped, suggesting coagulation factor deficiency. Elaborate coagulation tests showed factor XIII-deficiency.

Factor XIII deficiency: complete phenotypic characterization of two cases with novel causative mutations.

Coagulation factor XIII (FXIII) exists as heterotetramer (FXIII-A2B2) in the plasma and as dimer (FXIII-A2) in cells. Activated FXIII mechanically stabilizes fibrin and protects it from fibrinolysis by cross-linking fibrin chains and α2-plasmin inhibitor to fibrin. FXIII is essential to maintaining haemostasis, and its deficiency causes severe bleeding diathesis. Due to improper laboratory practices, FXIII deficiency is considered the most under-diagnosed bleeding disorder. The aim of this study was to demonstrate in two cases how FXIII deficiency is properly diagnosed and classified, and to compare results of laboratory analysis and clinical symptoms. FXIII activity from plasma and platelets was measured by a modified ammonia release assay, while FXIII-A2B2, FXIII-A and FXIII-B antigens were determined by ELISA. The exon-intron boundaries and the promoter region of F13A1 gene were amplified by PCR and the amplified products were analysed by direct fluorescent sequencing. FXIII-A mRNA in platelets was determined by RT-qPCR. Two children with severe bleeding symptoms were investigated. In both cases FXIII activity and FXIII-A antigen were undetectable in the plasma and platelet lysate. In the plasma no FXIII-A2B2 antigen was found, while FXIII-B antigen was >30% in both cases. Proband1 was a compound heterozygote possessing a known missense mutation (c.980G>A, p.Arg326Gln) and a novel splice-site mutation (c.1112+2T>C). Proband2 was homozygote for a novel single nucleotide deletion (c.212delA) leading to early stop codon. The discovered mutations explain the severity of clinical symptoms and the laboratory data. Methods precise in the low activity/antigen range are required to draw valid conclusion on phenotype-genotype relationship.

Iron autointoxication in a 16-year-old girl: a protective role for hepcidin?

Intentional iron overdose appears to be an increasingly common form of attempted suicide. We present a case of iron overdose in a 16-year-old girl who was found unconscious in her bed and brought to our emergency department. The most remarkable diagnostic findings were the patient's comatose condition, divergent eye position and positive Babinski foot pad reflexes. Laboratory tests showed hyperglycaemia and mild metabolic acidosis. A computed tomography scan of the cerebrum showed no signs of intracerebral haemorrhage or elevated intracerebral pressure. Toxicology screening showed no use of acetaminophen, ethanol or drugs of abuse. The patient was stabilized and monitored on the intensive care ward. When she woke up, she confessed to having taken Fero-Gradumet(®). Retrospectively analysed, the serum iron concentration in the first blood sample (seven hours after ingestion) was 62 µmol/L which corresponds with moderate iron intoxication. The patient received whole bowel irrigation with 2 L polyethyleneglycol solution and de-ironing treatment with intravenous deferoxamine 20 mg/kg in eight hours. She was discharged from the hospital after three days in a good clinical condition. Retrospectively, serum hepcidin concentrations were determined and evaluated in conjunction with serum iron concentrations and the installed treatment. Before medical de-ironing interventions were started, we saw that the serum iron concentration in our patient was already declining. At the same time, we observed a sharp increase in the serum hepcidin concentration. After normalization of serum iron concentrations, hepcidin normalized as well.

New erythrocyte and reticulocyte parameters on CELL-DYN Sapphire: analytical and preanalytical aspects.

INTRODUCTION: Extended RBC and reticulocyte parameters are useful in diagnosing functional iron deficiency and various other clinical conditions. The newest software of the CELL-DYN Sapphire measures extended RBC and reticulocyte parameters. The aims of the present communication were to assess the analytical aspects of these parameters compared with the Siemens Advia 120 analyzer, to study the effect of sample aging and to briefly explore their clinical usefulness in patients with anemia. METHODS: Blood samples were obtained from the routine workload of two hospital laboratories and were run on Siemens Advia and Abbott CELL-DYN Sapphire analyzers in parallel. Data analysis was performed using standard statistics. RESULTS: In total, 1416 patient samples were analyzed. There was close correlation in microcytic and macrocytic RBC (r(2) > 0.97) with small bias. The hypo- and hyperchromic RBC showed reasonable correlations, Advia 120 giving higher values. Reticulocyte MCV showed acceptable agreement, with significant proportional bias (Advia 8-9% higher). CELL-DYN Sapphire MCHr correlated rather well with Advia CHr (r(2) > 0.91) with significant absolute bias. Remarkably, the correlation data differed significantly between the two laboratories. It was found that aging of EDTA samples had significant effect on most of the RBC parameters. CONCLUSIONS: The new RBC parameters of CELL-DYN Sapphire generally correlated well with those of Advia 120, although significant systematic differences were present, particularly in reticulocyte MCH and MCV. These differences necessitate instrument-specific reference ranges and clinical decision values. To minimize preanalytical effects, these parameters should be measured in fresh blood samples.

Quality control of bone marrow cytology; organization and over 7 years experience in the south-west Netherlands.

To asses the quality of bone marrow cytology of hospital laboratories in the south-west Netherlands a proficiency testing program was implemented. Two sets of bone marrow and blood smears from two patients were sent to 20 hospital laboratories using a tight time schedule biannually. Required results consisted of differential counts of 500 bone marrow cells and 100 peripheral blood cells, together with the description of morphological abnormalities and final conclusions. Twice a year the collected review data were discussed in a plenary session which was also used for continuous education. Over the past 7 years 30 bone marrow samples were evaluated. The coefficient of variations of specific cells counts was large. The amount of correct conclusions ranged from 12% to 100% (median: 61%). Participant attendance of the meetings was 90-100%. The total cost of this scheme of proficiency testing approximately amounted euro7000 per year. The presented formulae for both proficiency testing and haematopathological/cytological education is feasible and fulfilled the need of the participants.

Haemolytic disease of the newborn because of rare anti-Vel.

Routine screening for maternal immunization in a 36-year-old woman revealed an alloimmunization against the high-incidence Vel antigen during a second pregnancy. Because of the development of immunoglobulin G-type anti-Vel, the infant developed haemolytic disease of the newborn, with severe jaundice and reticulocytosis. Phototherapy was needed to reduce hyperbilirubinaemia.

Fresh frozen plasma transfusion for reversal of prolonged post-anaesthesia apnoea.

An 18-year old woman admitted for tonsillectomy developed prolonged post-operative paralysis after anaesthesia with mivacurium. Investigation revealed a decreased cholinesterase activity because of a homozygous atypical and heterozygous K variant of the cholinesterase gene. Transfusion of fresh frozen plasma was associated with reversal of the respiratory paralysis and complete recovery.

Significance of elevated cobalamin (vitamin B12) levels in blood.

Elevated levels of serum cobalamin may be a sign of a serious, even life-threatening, disease. Hematologic disorders like chronic myelogeneous leukemia, promyelocytic leukemia, polycythemia vera and also the hypereosinophilic syndrome can result in elevated levels of cobalamin. Not surprisingly, a rise of the cobalamin concentration in serum is one of the diagnostic criteria for the latter two diseases. The increase in circulating cobalamin levels is predominantly caused by enhanced production of haptocorrin. Several liver diseases like acute hepatitis, cirrhosis, hepatocellular carcinoma and metastatic liver disease can also be accompanied by an increase in circulating cobalamin. This phenomenon is predominantly caused by cobalamin release during hepatic cytolysis and/or decreased cobalamin clearance by the affected liver. Altogether it can be concluded that an observed elevation of cobalamin in blood merits the a full diagnostic work up to assess the presence of disease.

Detection of polychlorinated biphenyls and dioxins in Belgian cattle and estimation of the maximal potential exposure in humans through diets of bovine origin.

The methodology used to detect a polychlorinated biphenyl (PCB)/dioxin contamination in a Belgian cattle population that was not exposed to the PCB/dioxin incident in 1999 is presented. This population is directly or indirectly destined for human consumption. The methodology consisted in the systematic sampling of all calf-fattening stations and groups of cattle destined for export, and in the random sampling of slaughter cattle. This approach is compared to the method described in directive 96/23/CE from the European Council. When PCB concentrations exceeded the tolerance level of 0.2 micro g/g body fat (seven congeners with numbers 28, 52, 101, 118, 138, 153, and 180), dioxins (seventeen 2,3,7,8-substituted congeners of PCDD and PCDF) were also determined. The prevalence of Belgian slaughter cattle with PCB concentrations above this cutoff was 0.3% (95% confidence interval: 0.01-1.50%). Results indicate that the incidence of contamination was minimal, with environmental origin and common in all industrial countries. The maximal potential exposure of an adult human consumer to dioxins through diet of bovine origin is estimated in two worst-case scenarios. The first one corresponds to the consumption of contaminated food products by a small number of consumers during a long period (local consumption) and the second simulates the consumption of contaminated products by a large number of consumers during a short period (supermarket purchase). The theoretical maximum daily intake of dioxins in adults was respectively 374 and 123 pg TEQ/d. The estimated maximum increase of dioxin body burden corresponds to 7 pg TEQ/g fat in the local consumption scheme and 0.07 pg TEQ/g fat in the supermarket consumption scheme.

[The significance of an elevated cobalamin concentration in the blood]. / De betekenis van een te hoge cobalamineconcentratie in het bloed.

Elevated levels of serum cobalamin may be a sign of a serious, even life-threatening, disease. Diseases such as chronic myeloid leukaemia, promyelocytic leukaemia, polycythaemia vera and hypereosinophilic syndrome are often accompanied by markedly elevated levels of cobalamin in the blood. A rise in the serum cobalamin concentration is one of the diagnostic criteria for polycythaemia vera and hypereosinophilic syndrome. In haematological disorders, the increase in circulating cobalamin levels is predominantly caused by enhanced production of haptocorrin. Several liver diseases such as acute hepatitis, cirrhosis of the liver, hepatocellular carcinoma and metastatic liver disease can also be accompanied by an increase in circulating cobalamin. In liver diseases, the increase in cobalamin is predominantly caused by cobalamin release during hepatic cytolysis and/or through decreased clearance of circulating cobalamin by the affected liver. Liver disorders are not an indication for determining the serum cobalamin concentration. However, a coincidentally observed elevated serum cobalamin concentration is reason for further investigation.

Evaluation of an automated hemostasis testing analyzer, the Trombolyzer Combi.

We evaluated the Trombolyzer Combi (Behnk Elektronik, Norderstedt, Germany), an automated hemostasis analyzer, in a clinical setting. Determination of prothrombin time (PT), activated partial prothrombin time (APTT), fibrinogen (FIB) and antithrombin (AT) were performed using Organon Teknika reagents. Determination of PT, APTT and FIB on a KC4 (Amelung, Germany) using Dade reagent (Dade Behring, The Netherlands) and determination of AT on a Hitachi 912 using Chromogenix reagent (Nodia, The Netherlands) were used as reference methods. Within-run and total precision of the tests were determined by measuring pooled plasma samples at various levels in duplicate twice daily for twenty days. For all tests the within-run and total precision of the Trombolyzer Combi was comparable or superior to the reference methods. Methods comparison was performed with 100 patient samples for PT, APTT and FIB and with 50 patient samples for AT. The correlation coefficients between the Trombolyzer Combi values and the results from the reference methods were between 0.87 and 0.98. No effect of hemolysis on the determination of the studied parameters was detected. However, bilirubinemia above 260 micromol/L and triglycerides above 9 mmol/L resulted in erroneous test results. In conclusion, it is shown that the Trombolyzer Combi performs equivalently or better than the reference methods and can be used as a state-of-the-art hemostasis analyzer in a clinical laboratory.