Relationship between sampling volume of primary serum tubes and spurious hemolysis

BACKGROUND

We planned a study to establish whether spurious hemolysis may be present in low volume tubes or partially filled tubes.

METHODS

Four serum tubes were collected in sequence from 20 healthy volunteers, i.e., 4.0 mL, 13 x 75 mm (discard tube), 6.0 mL, 13 x 100 mm half-filled, 4.0 mL, 13 x 75 mm full-draw and 6.0 mL, 13 x 100 mm full-draw. Serum was separated and immediately tested for hemolysis index (HI), potassium, aspartate aminotransferase (AST), and lactate dehydrogenase (LDH).

RESULTS

The HI always remained below the limit of detection of the method (< 0.5 g/L) in all tubes. No statistically significant differences were recorded in any parameter except potassium, which increased by 0.10 mmol/L in 4 mL full-draw tubes. No clinically significant variation was however recorded in any tube.

CONCLUSIONS

The results suggest that all types of tubes tested might be used interchangeably in term of risk of spurious hemolysis.

IgG4 immune response in Churg-Strauss syndrome

OBJECTIVE

T-helper type 2 responses are crucial in Churg-Strauss syndrome (CSS) and may enhance the production of IgG4 antibodies. The authors assessed the IgG4 immune response in CSS patients.

METHODS

The authors included 46 consecutive patients with CSS (24 with active and 22 with quiescent disease), 26 with granulomatosis with polyangiitis (GPA, Wegener's), 25 with atopic asthma and 20 healthy controls and determined serum IgG, IgM, IgA, IgE and IgG subclass levels. Tissue infiltration by IgG4 plasma cells was assessed in nine patients with CSS, 10 with GPA, 22 with chronic sinusitis (11 with and 11 without eosinophilia).

RESULTS

IgG4 levels were markedly higher in active CSS patients than in controls (p<0.001 vs all control groups). Serum IgG4 correlated with the number of disease manifestations (r=0.52, p=0.01) and the Birmingham vasculitis activity score (r=0.64, p=0.001). Longitudinal analysis in 12 CSS cases showed that both the IgG4 level and IgG4/IgG ratio dropped during disease remission (p=3×10(-5) and p=6×10(-4), respectively). Tissue analysis did not show an increased IgG4 plasma cell infiltration in CSS biopsies compared with control groups.

CONCLUSIONS

Serum IgG4 levels are markedly elevated in active CSS and correlate with the number of organ manifestations and disease activity.

Italian multicentre study for application of a diagnostic algorithm in autoantibody testing for autoimmune rheumatic disease: conclusive results

AIM

The presence of specific auto-antibodies in serum (i.e., antinuclear antibodies or ANA, anti-extractable nuclear antigens or anti-ENA, and anti-double stranded DNA or anti-dsDNA ) is one of the major criteria in the diagnostics of Autoimmune Rheumatic Disease. As such, the request for these tests has grown exponentially in laboratory practice. The aim of this study is to describe the implementation of a joint laboratory-clinics guideline for reducing clinically inappropriate requests for autoantibody testing in a broad geographic area (Parma, Modena, Piacenza, Reggio-Emilia) for the diagnosis of Autoimmune Rheumatic Disease.

METHODS

This study, supported by a Regional grant for innovative research projects started in January 2008, is an observational research aimed at comparing the number of ANA, anti-dsDNA and anti-ENA testing as well as the percentage of positive test results before and after implementation of the diagnostic algorithm in hospitalized patients. A multidisciplinary team consisting of clinical immunologist and laboratory scientists was established, with the aim of collecting and analysing diagnostic criteria, clinical needs, laboratory report formats, analytical procedures, as well as the number of tests performed. The laboratory results and the clinical protocol were both validated by data emerging from the clinical follow-up studies.

RESULTS

A joint guideline for auto-antibody testing, placing ANA test at the first level, has been developed and implemented since January 2009. The results for the period January-June 2009 (12,738 tests) were compared with those of the same period in 2008 (13,067 tests). A significant reduction in the number of anti-dsDNA (-26%) and anti-ENA (-15%) was observed. The percentage of second-level tests positivity after implementation of the diagnostic protocol had also consistently increased for both ENA (13% vs 17%) and dsDNA (9% vs 11%).

DISCUSSION

The development and implementation of algorithms for the diagnostics of Autoimmune Rheumatic Disease in hospitalized patients was associated with a reduction in the number of second-level tests, but also with an increased diagnostic specificity. This outcome attests that close collaboration and audit between clinicians, laboratory specialists and healthcare services is effective to develop efficient diagnostic algorithms for both hospitalized patients and outpatients.

Interference by heterophilic antibodies in immunoassays: wrong increase of myoglobin values

Aim of this work is to illustrate how analytical interference in immunoassay may produce serious errors in clinical laboratory results. The sophisticated quality assurance schemes used in many laboratories do not identify erroneous results arising from aberrant samples. Recently attention has been focused on the incidence and implication of false-positive results arising from the presence of certain substances in a patient's serum that interfere with one or more steps in immunoassays. In this paper, we present the case of a 92 year-old woman whose plasma myoglobin concentrations falsely increased when measured using the Beckman Access assay. We demonstrated that heterophilic antibodies accounted for the falsely increased myoglobin values, and we suggest how to resolve such situations.

[Bence-Jones proteinuria and kidney's damages]

Bence-Jones proteinuria consists in monoclonal light chains into the urine. Normally kidney eliminates light chains but, when light chains are in excess, they make histological and functional lesion to tubules, glomerulus and vessels both by direct action, or lysosomal enzyme releasing or making tubular obstruction. We analyse these kidney's damages from the morphological and functional point of view. Bence-Jones proteinuria can be detected by urinary protein electrophoresis, immunoelectrophoresis, immunofixation electrophoresis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, two-dimensional electrophoresis and capillary electrophoresis.

Mini–Cardiopulmonary Bypass System: Results of a Prospective Randomized Study

BACKGROUND

We studied postoperative mortality and morbidity after coronary artery bypass graft surgery performed using the mini-extracorporeal circulation (MECC) system.

METHODS

From June 2001 to June 2002, we randomly enrolled 60 patients who underwent isolated elective coronary artery bypass graft surgery, and were operated on with the MECC system (30 patients: group A) or standard cardiopulmonary bypass (30 patients: group B). Serial blood samples were collected to evaluate the main preoperative, intraoperative, and postoperative clinical and biological variables; and to measure hemolysis, interleukin-6 cytokine, and plasma C-reactive protein release.

RESULTS

A more stable hemoglobin level was detected in group A. The platelet count did not show a significant difference between the two groups. Interleukin-6 cytokine release showed higher values in group B, although no difference between groups was statistically significant. The time course of circulating plasma C-reactive protein concentration exhibited the same increase in both groups. Plasma free hemoglobin levels showed higher hemolysis peaks in group B, although a statistical significant difference was detected only at 4 hours after surgery. A higher cardiac index and reduced systemic and pulmonary vascular resistance index in the early postoperative period were found in group A at postoperative time 30 minutes.

CONCLUSIONS

Our experience shows that MECC offers satisfactory clinical benefits in terms of good hemodynamic support, safety, and low morbidity, although the study failed to demonstrate a significant clear superiority of MECC versus conventional cardiopulmonary bypass. The results need to be confirmed by a larger prospective, randomized study comparing MECC and standard cardiopulmonary bypass.