[About the choice of acceptability limits in external quality assessment schemes]

Quality control schemes are a practical tool used in clinical laboratories and an essential element for any quality assurance process. In France, external quality assessment schemes (EQAS) can be mandatory (as national quality control organized by AFSSAPS) or voluntary as those suggested by French associations (ProBioQual, CTCB or Asqualab). These EQAS usually evaluate participants according to their performances: this ranking depends on acceptability limits which are here compared. Various examples based on ProBioQual's background illustrate difficulties to plan out analytical quality specifications. A comment is given about the best criteria (state of the art or biological variation mainly) to be considered to delimit analytic goals. This discussion includes approaches suggested by French committee on accreditation (Cofrac). All criteria could be criticized but it is important to compare oneself laboratory to peers and also to take account of biological variation.

French experience of quality assessment of quantitative urinary analysis

Since 1986, clinical biochemists from the Rhône alpes area, in collaboration with a non-profit-making association (Pro Bio Qual), have been conducting an inter-laboratory quality assurance program for quantitative urine analysis. We investigated the precision and accuracy of individual methods and measurement systems routinely used in the monthly control for 13 analytes: albumin, alpha-amylase, calcium, chloride, creatinine, glucose, magnesium, phosphorus, potassium, total protein, sodium, urea, and urate. The number of laboratories participating in the program increased from 60 in 1986 to 277 in 1999. In 1986, the greatest inter-laboratory imprecision occurred in the assay of urinary total protein, because the commonly used sulfosalicylic acid turbidimetric methods displayed poor precision. Since 1989, the increasing use of pyrogallol red or Coomasie Blue dye colorimetric methods has improved inter-laboratory precision markedly. The acceptable precision and good practicability have encouraged the general use of the pyrogallol red method. As for albumin analysis, which uses a specific immunologic method, the precision was reasonably good. Quality assessment of chloride and sodium decreased when the method performance improved for other analytes (calcium, creatinine, glucose, magnesium, phosphorus, potassium, urea, urate). This program has helped the laboratories to improve the quality of quantitative urine analysis, particularly for total protein.

External quality assessment of urine analysis in Europe. Results of a round table discussion during the symposium 'From uroscopy to molecular analysis', Seeon, Germany, September 18-20, 1999

Interlaboratory surveys on urine quantities have only recently been introduced in several European countries. Representatives of 10 European countries exchanged their experiences during an international urinalysis meeting held in September 1999. Although still not mandatory in most areas, more than 5000 laboratories participated in external quality assessment programs in the countries represented. Qualitative (test strips and microscopic morphology) as well as quantitative chemical and immunochemical quantities were included. The maximal allowable deviations are reported as well as methods used to determine target values. Consensus scales up to reference methods were applied. The participants agreed that quality criteria need to be defined separate from those already existing for plasma/serum analytes. Besides higher biological variables and different medical needs, less standardisation of methods to quantify urine constituents was observed as a major cause of higher interlaboratory differences.

Usefulness of the prognostic inflammatory and nutritional index (PINI) in hospitalized elderly patients

The prognostic inflammatory and nutritional index (PINI) is a simple scoring system of overall health which aggregates two blood markers of inflammatory (C-reactive protein and alpha(1)-acid glycoprotein) and of nutritional (albumin and transthyretin) states. This study was undertaken with a view to evaluate, in comparison to currently used predictive approaches, the potential usefulness of PINI to forecast hospital mortality and outcome of patients hospitalized in an acute geriatric unit. 1,066 elderly patients, aged 82.7 +/- 6.6 years and fulfilling inclusion criteria, were enrolled in the study. Logistic regression analysis and calculation of relative risk (RR) were carried out for epidemiological data with a cut-off value of 25 for PINI. Immediate mortality (7.9%) of admissions) was predicted by PINI > or = 25 (RR = 4.34). Only 387 patients (36.3%) could rejoin their residence location (home or family). A sizeable proportion of acute patients (55.8%) failed to recover and/or developed diseased states requiring chronic care management. Incapacity to return home was predicted by PINI > or = 25 (RR = 2.04). Hypoalbuminaemia < or = 30 g/L was not found a predictor of mortality but was associated with total disability (RR = 9.08). The optimal PINI cut-off value to predict mortality was calculated at 8.8 using the ROC analytic approach. We conclude that the PINI formula is helpful to predict both nearest lethality and chronic institutionalization. This scoring system should take a place within the battery of tests used to identify and to follow up acutely ill elderly patients at risk of major complications.

Implication of cytokines in the aggravation of malnutrition and hypercatabolism in elderly patients with severe pressure sores

The objectives of this work were to study the production of the cytokines Interleukin 1 (IL-1), Interleukin 6 (IL-6), and tumour necrosis factor (TNF) in elderly patients with severe pressure sores and to assess their potential contribution to the aggravation of malnutrition. Nineteen bedridden patients with stage III or IV pressure sores, 12 bedridden patients free from pressure sores, but at risk of them, and 12 control patients without risk of pressure sores were studied. Nutritional status was evaluated using anthropometry, serum albumin, prealbumin, retinol-binding protein analyses, and delayed hypersensitivity skin tests. Acute-phase proteins (APP), cortisol, and cytokines blood levels together with cytokine production were measured. Nutritional status was poor in patients with sores and their APP, and IL-6 blood levels were significantly increased; IL-1 and TNF serum concentrations were not elevated in these patients. A significant difference in cortisol levels was observed between patients with stage III and IV sores. A local cytokine origin (especially IL-6, and also IL-1) was demonstrated. Thus cytokines, mainly IL-6, produced by tissue cells in damaged areas together with cortisol may aggravate malnutrition and hypercatabolism in patients with sores.