ABSTRACT
Among the general causes of preanalytical variability, one of the most important is represented by the error due to the sample evaporation. The measure of the sodium and potassium concentration on the serum pools and on a saline solution has allowed to define the different variables effect. On the ground of the experimental data the error by operative loss is: a) directly proportional to the evaporative time; b) directly proportional to the exposition temperature for values of relative humidity of 60-70%; c) remarkably influenced by the air-flow in the environment; d) widely conditioned by the container-geometry and particularly by the height/diameter ratio; e) the minimum evaporative loss happens with cups filled up to the 50-60%, with much higher values below the 30% of filling; f) the influence of the different cup composition (either glass or plastic) as well as the different medium (either serum or saline solution) is negligible. The actual analytical error can be kept into moderate and acceptable ranges (lower than 1% in the eight hours) if the environmental ventilation is controlled, and if it is chosen the proper shape of the cup, the right sample cup capacity and a suitable operative procedure. In particularly unfavourable conditions, on the contrary, the entity of the evaporative error can even exceed the 100% in the eight hours time of the daily work.
Subject(s)
Blood Specimen Collection/standards , Potassium/blood , Sodium/blood , Blood Specimen Collection/instrumentation , Environment, Controlled , Evaluation Studies as Topic , Humans , Humidity , Temperature , Time FactorsABSTRACT
The plasma levels of alpha-lipoproteins, triglycerides, cholesterol, bilirubin, ALT and AST were followed serially in a group of 10 patients with acute viral hepatitis. Hypertrygliceridaemia, low level of cholesterol and very low level of alpha band of the lipoproteins were found at the onset of the disease. Alpha-lipoprotein reappeared gradually during the course of the disease and was sensitive indices of improvement of liver function. A negative linear correlation was found between alpha-lipoprotein and total bilirubin and between alpha-lipoprotein and ALT.
Subject(s)
Hepatitis, Viral, Human/blood , Lipoproteins, HDL/blood , Adolescent , Adult , Aged , Bilirubin/blood , Cholesterol/blood , Female , Humans , Male , Middle Aged , Transaminases/blood , Triglycerides/bloodABSTRACT
The comparative study of a determined time method, according to King-Armstrong, for the measurement of the alkaline phosphatase activity in serum and of a kinetic method consents us to make the following points: 1) the reagents used in the King-Armstrong method are easily prepared and are stable for months, with the sole addition of cloroform to the substrate and to the buffer to avoid the growth of moulds. 2) The substrate used for the kinetic method undergoes spontaneous Xydrolysis in acqueous solution, which makes it possible to keep it refrigerated for a limited number of days. Freezing at - 20 degrees C does not improve the situation. 3) The degree of precision within the series and between the series is the same for the two methods, and very good. 4) From the working point of view the method of "determined time" is advantageous for few samples, while the kinetic method becomes preferable when the number of samples goes over 20 and 30 a day, provided that it is linked with the suitable automatic apparatus. 5) The results of the measurement of the enzyme activity found with the two methods on 120 sera of normal and pathological subjects have shown good correlation, confirming the clinical diagnostic value of the results obtained by the kinetic method, which uses a transphosphorilant buffer and their congruency with those obtained by the classical King-Armstrong method.
