[Costs and prices of laboratory services]. / Laboratorieydelsers omkostninger og priser.

Cost accounting is performed in private and public laboratories. Guidelines for these activities are required and with this objective in mind, the Board of the Danish Society of Clinical Chemistry commissioned a working group to produce a position paper which is presented now in this report. The report discusses the objectives, the principles and the general requirements for cost accounting. The significance of information on costs for the clinicians' rational use of the laboratory is also illustrated. The working group points out that prerequisites for lucid and appropriate costing guidelines are clarification of which purposes information on costs are meant to serve, identification of the relevant cost centers and quality assurance of laboratory services to a defined extent. It is common practice to express laboratory costs as costs per test. The report advocates calculation of the cost per patient contact, i.e. the overall costs for laboratory service in a given investigative situation.

A 12-month study on changes in the barrier properties of denture-loaded palatal mucosa in immediate denture wearers.

The changes of barrier properties and surface cytology of the palatal mucosa during a denture-wearing period of 12 months has been studied in 18 adult subjects. Transmucosal rates of water transport and that of a 1.10 osmol sucrose solution were registered gravimetrically before denture treatment, after 3 months and after 12 months of denture wearing according to procedures described earlier. The keratinization pattern and the leukocyte migration were evaluated from scrapings taken from the palate and the fitting surface of the denture. The clinical appearance was recorded photographically. After 3 months of denture wearing only minor changes in permeability and surface cytology were observed. After 12 months a distinct grouping of the material was possible with regard to permeability reactions, as seven subjects showed no changes, five subjects demonstrated an increased osmotic activity in the palatal mucosa, and six subjects exhibited a severely decreased barrier function. The color photos revealed inflammatory reactions of the palatal mucosa in the latter group. The cytologic observations showed after 12 months a significant decrease in the proportion of anucleated cells in the inflammatory group, but only minor changes in the remaining material.

Barrier properties of inflamed denture-loaded palatal mucosa to water.

The barrier property of inflamed palatal mucosa to water has been studied in eight adult edentulous persons with a generalized denture stomatitis, by measuring the transmucosal water flow under varying osmotic gradients. Flow rates were registered gravimetrically in solute saturated filter paper discs after 10-min periods of mucosal contact, using solutions with an osmolarity of 0, 0.25, 0.30, 0.38, 0.50 and 0.75 osmol sucrose/l. The histology of the mucosal areas was evaluated from cytologic scrapings, and biopsy material from two persons. The inflow with use of pure water was 2.98 mg/cm2/10 min, being about three and a half times greater than through the intact mucosal surface. The point of isotony of the inflamed mucosa ranged between 0.30 and 0.36 with a mean value of 0.33 osmol/l, thus being of the same magnitude as in plasma and tissue fluid. The observations from the biopsy material were in accordance with earlier histological evidence from generalized denture stomatitis, indicating that the permeability properties of the inflamed mucosa belonged to epithelial cell layers located in the lower part of the spinous layer.

Changes in the water permeability of palatal mucosa after complete denture treatment.

The water permeability of the human palatal mucosa has been studied in 12 persons with 1 year of full maxillary denture experience and 10 persons without dentures. Transmucosal water transport rates were studied gravimetrically with the use of solutesaturated discs of filter paper in contact with the mucosa, in accordance with earlier described procedures (KAABER 1973a, b). The inflow of water through clinically healthy mucosa was at the same level in both groups. After use of a 1.10 mol sucrose solution a significant increase in the inflow was observed in the denture wearers group, which suggested an increased amount of osmolytes in the mucosal surface. Two denture wearers with a slightly inflamed mucosal surface showed an increased inflow after use of water and a corresponding strong outflow after use of the sucrose solution, indicating a partial loss of the mucosal barrier function.