Anion gap: A measurement of the interval between the sum of routinely measured cations minus the sum of the routinely measured anions in the blood. The anion gap = (Na+ + K+) - (Cl- + HCO3-) where Na-is sodium, K+ is potassium, Cl-is chloride, and HCO3- is bicarbonate.
Precision: Precision refers to the reproducibility of this result that is you get the same result every time you try. Characteristics of Accuracy and Precision: Accuracy: Accuracy refers to the closeness of a measurement to its actual or real value. Precision: Precision refers to the regularity of obtaining the same result frequently. Usage: Accuracy: The concept of accuracy is encountered in measurement in physics and industry.
1 The more common definition is that accuracy is a level of measurement with no inherent limitation (ie. 2  free of systemic error, another form of observational error).ith regard to accuracy we can distinguish: 1  the difference between the mean of the measurements and the reference value, the bias. 2  Establishing and correcting for bias is necessary for calibration. 3  the combined effect of that and precision.