A comparison of three column agglutination tests for red blood cell alloantibody identification.

OBJECTIVE: Commercial kits of column tests for pre-transfusion testing have progressively replaced conventional tube tests in most laboratories. Aim of this study was to compare three commercial test cell panels for the identification of irregular red blood cell (RBC) alloantibodies. Overall, 44 samples with a positive indirect antiglobulin test (IAT) by routine testing were used for comparison of following panels: Ortho RESOLVE® panelC (Ortho Clinical Diagnostics (OCD), Milan, Italy), ID-DiaPanel(-P) (Bio-Rad Laboratories, CA, USA) and Identisera Diana(P) (Grifols, Barcelona, Spain). Column agglutination techniques were used, with microtubes containing either microgel (Bio-Rad/Grifols) or glass bead microparticles (Ortho). RESULTS: Alloantibody identification was possible in 38 samples, of which identical identification was shown in 33 samples by all methods. The remaining samples showed differences between certain methods, with the gel card system being superior to the glass card system for analyzing stored samples Considering that not all samples were evaluated in all three methods, the concordance rate reached 100% between Bio-Rad and Grifols, 90.5% between Bio-Rad and OCD, 86.5% between OCD and Grifols and 90.5% between all methods. Although differences in sensitivities were seen for specific antibodies, the three methods showed comparable performance for the identification of RBC alloantibodies.

Serum amyloid A is independently related to apolipoprotein A-I but not to HDL-cholesterol in patients with angina pectoris.

BACKGROUND: Inflammation processes are considered important links between classical lipid risk factors and the progression of atherosclerosis. The interrelationship of high density lipoproteins (HDL) and apolipoprotein apoA-1 with acute phase proteins and cytokines was examined in a clinical setting of patients with angina pectoris. METHODS: On exclusion criteria (myocardial infarction, heart failure, CHD>2 years, anticoagulant therapy), 198 patients were recruited and were subdivided according to angiographically documented stenosis, no stenosis vs. =50% stenosis, in accordance with CASS guidelines. Lipids, apoA-1 and apoB, C-reactive protein (hs-CRP), fibrinogen, serum amyloid A (SAA) and cytokines (IL-6, IL-8, IL-10, IL2R, TNFα) were measured. RESULTS: Low HDL-C (and apoA-I) is associated with advanced coronary stenosis (=50%) and with the number of diseased vessels, independent of age, gender, diabetes, smoking and lipid-lowering therapy. In contrast to hs-CRP and fibrinogen, SAA as well as cytokine levels were not significantly associated with stenosis. SAA (P=0.0003) and diabetes (P=0.0002) were strong predictors of apoA-I concentration independent of age, gender, BMI, smoking, CRP, as well as IL-6 in a multiple regression model. High SAA (P=0.0067) and TG (P=0.0123) were significant predictors of apoA-I/HDL-C ratio. However, SAA was not independently related to HDL-C. CONCLUSIONS: SAA is independently and inversely related to apoA-I but not to HDL-C in patients with angina pectoris, reflecting the effect of SAA on the quality of HDL particles. However, HDL-c but not SAA is inversely related to the degree of coronary artery stenosis.

Spuriously high thyrotropin values due to anti-thyrotropin antibodies in adult patients.

BACKGROUND: Three adult patients presented with unexpectedly high thyrotropin (TSH) concentrations that were discordant with clinical and biochemical findings of euthyroid or hyperthyroid status. METHODS: Antibody interference in the TSH immunoassay (Roche) was investigated by polyethylene glycol (PEG)-pretreatment, heterophilic blocking tube (HBT)-pretreatment, rheumatoid factor (RF) testing, immunofixation, protein A adsorption, and gel filtration chromatography (GFC). RESULTS: PEG-precipitation yielded<20% recovery of serum TSH, whereas HBT-pretreatment did not decrease TSH test results. RF-testing and immunofixation were negative. Protein A adsorption and GFC demonstrated the presence of TSH-immunoglobulin complexes in serum. CONCLUSIONS: Interference by TSH-immunoglobulin complexes should be ruled out in euthyroid and hyperthyroid patients presenting with inappropriately increased or non-suppressed TSH values.

Circulating oxidized low-density lipoprotein: a biomarker of atherosclerosis and cardiovascular risk?

Low-density lipoproteins (LDLs) are susceptible to structural modifications by oxidation, particularly the small dense LDL particles. The formation of lipid peroxidation derivates, such as thiobarbituric reactive substances, conjugated dienes, lipid hydroperoxides, and aldehydes, is associated with changes in apolipoprotein conformation and affects the functional properties of LDLs. Oxidized LDL (oxLDL) formation in the subendothelial space of the arterial wall is a key initiating step in atherosclerosis because it contributes to foam cell generation, endothelial dysfunction, and inflammatory processes. In the last decade, immunoassays were developed using monoclonal antibodies against oxidation-dependent epitopes of LDL which made it possible to directly measure oxLDL in the circulation. Increased circulating oxLDL concentrations have been related to cardiovascular disease in some studies, although not always independently after adjustment of classical lipid markers. The Asklepios Study, investigating 2524 healthy middle-aged subjects, showed that circulating oxLDL is affected by many biological and lifestyle factors, as well as (generalized) subclinical atherosclerosis.