Critical steps in electronic volume quantification of gingival crevicular fluid: the potential impact of evaporation, fluid retention, local conditions and repeated measurements

Background and objectives: Various methodological factors may operate during clinical gingival crevicular fluid (GCF) sampling, volume quantification or subsequent laboratory analysis. For precise volume quantification, specific concern for generation and maintenance of a reliable calibration curve, the potential risk of GCF loss as a result of evaporation or fluid retention on actual volume and the impact of local conditions is needed because each of these factors may act as a source of subsequent volumetric distortions. Thus, the present study aimed to analyse the impact of sample transfer time on the rate of evaporation and the possibility of fluid retention, and the impact of local conditions and number of replicated measurements on the reliability of calibration data. Materials and methods: To analyse evaporative errors, standardized Periopaper® strips provided with known test volumes (0.1 µl, 0.2 µl, 0.5 µl and 0.6 µl) were transferred to Periotron 8000® with different time intervals (immediately, 5 s, 30 s and 60 s). For fluid retention, after quantifying the actual volume of the strips provided with known volumes (0.1 µl and 0.6 µl) of two test fluids, a second set of measurements was performed using dry strips. To determine the impact of local conditions (temperature and humidity) and the validity of 3, 5 and 20 replications (0.0–0.6 µl with 0.1‐µl increments) on device calibration for 20°C and 25°C, electronic readings were obtained from three devices at three different locations. Differences in volumetric data in each experimental design were statistically analysed. Results: No significant fluid loss was observed within 5 s, but evaporation clearly led to volumetric distortions with extending transfer times (30 s or 60 s) (p