Clin Chem Lab Med
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Serum amyloid A protein levels as a possible aid in the diagnosis of acute appendicitis in children.
Hematological and biochemical tests, including white blood cell count (WBC), C-reactive protein (CRP) and other acute-phase reactants, have been used in the diagnosis of acute appendicitis. However, there is controversy among physicians about the value of this practice in children. The objective of our study was to evaluate serum amyloid A protein (SAA) levels in children with confirmed acute appendicitis and to compare the sensitivity and specificity of this marker of inflammation with those for WBC and CRP. ⋯ The sensitivity and specificity of these methods were 76% and 75% for WBC>10.0 x 10(9) /L, 62% and 94% for CRP>10 mg/L and 86% and 83% for SAA >45.0 mg/L, respectively. Circulating SAA levels have better discriminatory value than WBC or CRP in the assessment of acute appendicitis in children. Thus, this test appears to be of higher value than the current standards of care in the diagnosis of this condition.
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Comparative Study
Population-specific reference values for thyroid hormones on the Abbott ARCHITECT i2000 analyzer.
Reliable reference ranges are important in the interpretation of laboratory data, and it is incumbent on each laboratory to verify that the ranges they use are appropriate for the patient population they serve. The objective of this study was to determine population-specific reference ranges for thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3) and total triiodothyronine (TT3) on the Abbott ARCHITECT 12000 analyzer. For this study, we used human serum samples collected from a population in Castilla y León, Spain. ⋯ Within the hospitalized patient group, significant differences between men and women were found for TSH only, and age-related differences were significant for TSH, fT3 and TT3. Our findings are basically in accordance with previously published results for fT3, TT3 and TSH, but for fT4 our results differ from other data in the literature. This highlights the need for laboratories to confirm that the reference ranges they use are appropriate for the population they serve.
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The aim of this study was to define the use of a new cardiac troponin I (cTnI) assay for emergency patients with chest pain and no specific electrocardiographic changes consistent with the presence of ischemia. Patients (n = 106) admitted in Emergency/Cardiology Departments for chest pain and suspicion of acute coronary syndrome (ACS) were randomized into two diagnosis groups (ACS or non-ACS) by two independent cardiologists. cTnI measurements were performed at admission, and 6 hours and 12 hours later with a new generation assay (Access AccuTnI, Beckman Coulter). ⋯ Precision (coefficient of variation) was 8% at this level, PPV 97% and specificity 98%. This new decisional value is now used in our institution and could be included in standard care guidelines to improve the management of patients presenting chest pain in emergency departments.
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In randomized controlled trials, prior to statistical analysis, the data are checked for outliers and erroneous data. Statistical tests are, traditionally, not very good at distinguishing between errors and outliers, but they should be able to point out main endpoint results closer to expectation than compatible with random sampling. ⋯ In randomized controlled trials, main endpoint p-values larger than p=0.95 will be rare, because they would indicate similarities closer than compatible with a normal distribution of random data samples. Also very low p-values like p<0.0001 will be rarely encountered, because it would mean that the trial was overpowered and should have had a smaller sample size. It would seem appropriate, therefore, to require investigators to explain such results and to consider rejecting the research involved. So far, in randomized controlled trials the null-hypothesis is generally rejected at p<0.05. Perhaps we should consider rejecting the entire study if the main endpoint p-values are >0.95 or <0.0001.
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In idiopathic recurrent urolithiasis (IRCU) calcium oxalate and calcium phosphate are components of stones. It is not sufficiently known whether in urine the nucleation (liquid-solid transition) of each salt requires a different environment, if so which environment, and whether there is an impact on stone formation. Nucleation was induced by in vitro addition of oxalate or calcium to post-test meal load whole urine of male stone patients (n=48), showing normal daily and baseline fasting oxaluria. ⋯ Conversely, when the calcium excess was extreme, calcium-rich hydroxyapatite developed, followed by calcium oxalate; F-Cit, not total and complexed citrate, was decreased in IRCU vs. male controls; F-Cit rose pH-dependently, and the ratio F-Cit at original pH vs. F-Cit at pH 6.0 correlated inversely with the nucleation index T-Ox/T-Ca; MA correlated inversely with the ratio F-Cit at pH 6.0, respectively, original pH, but directly with the urinary albumin/non-albumin protein ratio. In summary 1) to study calcium oxalate and calcium phosphate nucleation in whole urine of IRCU patients is feasible; 2) at this crystallization stage the two substances, dominant in calcium stones, appear intimately linked, 3) in stone-forming urine, calcium phosphate may be ubiquitously present, likely as particles < 0.22 microm; 4) together with co-precipitation of calcium oxalate and calcium phosphate, low F-Cit and alteration of proteinuria may act in concert and accelerate stones.