Status of serum-calcium and -albumin measurement in Argentina assessed in 300 representative laboratories with 20 fresh frozen single donation sera.

BACKGROUND: The Fundación Bioquímica Argentina (FBA) performs external quality assessment (EQA) of >3200 laboratories. However, FBA realizes that sample non-commutability and predominant use of heterogeneous systems may bias the estimated performance and standardization status. To eliminate these confounding factors, a study using frozen single donation sera was undertaken with the focus on serum-calcium and -albumin measurement. METHODS: Target values were established from the results produced with homogeneous systems. In groups of n=7, system effects were investigated. Laboratory performance was evaluated from the correlation coefficient r between the measurement results for all sera and the target values. This allowed ranking of the laboratories and judgment of the deviation for individual samples (total error) against a 10% limit. The total error specification was a deviation for ≥ 5 samples exceeding 10% and/or causing a result outside the laboratory's reference interval. RESULTS: For calcium (n=303) (range: 2.06-2.42 mmol/L), 81 laboratories had an r-value <0.6, 43 even <0.4; the total error was relevant for 97 (10% limit) and 111 (reference interval) laboratories. For albumin (n=311) (range: 34.7-45.7 g/L) r was <0.7 (<0.4) in 44 (16) laboratories; 83 and 36 laboratories exceeded the total error criteria. Laboratories using homogeneous systems were generally ranked higher by correlation. System effects were moderate for calcium, but significant for albumin. CONCLUSIONS: The study demonstrated the need to improve the quality and harmonization of calcium and albumin testing in the investigated laboratories. To achieve this objective, we promote co-operation between laboratories, EQA provider and manufacturers.

Effects of an angiotensin-converting enzyme inhibitor (ramipril) on inflammatory markers in secondary prevention patients: RAICES Study.

AIMS: To evaluate the hypothesis that angiotensin-converting enzyme inhibitor therapy with ramipril reduces baseline levels of C-reactive protein in patients at high cardiovascular risk. METHODS: Secondary prevention patients were screened for eligibility and treated with ramipril for 6 month. Baseline and 6-month highly sensitive C-reactive protein levels were determined. RESULTS: A total of 77 patients were analyzed. The median highly sensitive C-reactive protein concentration at baseline was 2.17 mg/l (interquartile interval 0.97-4.54); whereas in post-treatment, the median was 1.70 mg/l (interquartile interval 0.88-3.41), P=0.0009. Patients were stratified according to risk level determined by baseline highly sensitive C-reactive protein levels: low-risk (<1 mg/l), intermediate risk (1-3 mg/l) and high risk (>3 mg/l) The reduction in highly sensitive C-reactive protein occurred at the expense of the high-risk group (baseline 5.02 mg/l, post-treatment 3.3 mg/l, P<0.0001), with no differences in the other groups. In multiple regression analysis, the reduction observed in the high-risk group could not be explained by baseline treatment or change in any of the variables analyzed. CONCLUSION: Highly sensitive C-reactive protein levels were reduced after a 6-month ramipril therapy in secondary prevention patients, suggesting an anti-inflammatory effect of angiotensin-converting enzyme inhibitors. Future investigations will be done to confirm these results, and to investigate how angiotensin-converting enzyme inhibitor treatment elicits anti-inflammatory effects.