Abstract
Background: Pre-analytical, analytical, or post analytical variations can induce, change, or alter the tests results. Laboratory errors lead to unnecessary delays in test report and also increased costs by repeat samples which have become a pain to the patients.

Aims and Objectives: The aims of this study were to determine alterations in the concentration of serum sodium (Na+), potassium (K+), and ionized calcium (Ca++) concentration with reference to air exposure, time, temperature, and humidity.

Materials and Methods: Fifty samples as case and 50 samples as control were included from a normal healthy population in this study. After getting the samples, first readings were taken for case samples and were uncapped and the remaining samples were set aside capped at 24°C, 20% humidity for half an hour and followed by second reading which was taken.

Results: Variation in the mean serum sodium between groups is 0.06 mEq/L (0.04%) and 0.08 mEq/L (0.07%) which is very negligible and insignificant (P > 0.05). The mean level of serum K+ in cases is 4.35 mEq/L and in controls is 4.27 mEq/L. After half an hour, the mean level of serum K+ in cases is 4.51 mEq/L and, in controls, is 4.29 mEq/L. Hence, the variation in results in cases is 0.16 mEq/L (3.68%) and in controls is 0.02 mEq/L (0.47%) which is highly significant (P < 0.05). The mean level of serum Ca++ in cases is 1.15 mmol/L and in controls is 1.17 mmol/L. After half an hour, the mean level of serum Ca++ in cases is 1.09 mmol/L and in controls is 1.16 mmol/L. Hence, the variation in results in cases is 0.06 mmol/L (5.22%) and in controls is 0.01 mmol/L (0.85%) which is highly significant (P < 0.05).

Conclusion: Air exposure significantly alters the serum K+ and Ca++ level, but the alteration in serum Na+ level is not significant.

Key words: Serum Sodium; Serum Potassium; Serum Calcium; Air Exposure; Temperature