Electrolyte abnormalities can precipitate life threating events. Critical ill patients require urgent evaluation of electrolyte to initiate therapy. In such situation, rapid and accurate assessment of electrolyte abnormality may enable the institution focused therapies. The rapidity of such assessment, particularly in developing countries, is often delayed in transporting samples to the central laboratory either due to lack of sufficient number of manpower, or the absence of rapid transit system (RTS). These delays could unfavorably impact outcomes. Moreover, it is important to measure the electrolyte and hemoglobin level in older patients, patients with renal dysfunction, patients who are taking diuretics. In addition, the patients with severe anemia are waiting for the blood transfusion treatment and those with hyperkalemia need reduce the serum potassium level immediately. Such biomarker information can be quickly obtained by point of care testing(POCT)with an arterial blood gas analyzer. Thus, emergency management can be quickly performed.    Point of care testing (POCT) has thus been increasingly used in the Emergency department (ED) and ICU to enable the rapid assessment of electrolyte and arterial blood gas (ABG) abnormalities. Despite the advantage of a rapid turnaround time with POCT, concerns have been raised regarding the accuracy and reliability of POCT devices. Conflicting results from various studies, probably due to the use of different device, add to the concerns. While some studies concluded that results differed significantly for plasma sodium and chloride concentrations, other also found significant difference in potassium value. Thus, it is not uncommon to find clinician using the POCT results to act in an emergent situation while sending an additional sample to the central laboratory to confirm the POCT value. The difference in the value obtained have been attributed to the use of different devices, the effect of transport of sample as well as the type of sample used. This prospective study will be performed to determine whether the VBG and laboratory measurements of potassium, sodium, and hemoglobin levels are equivalent, and Whether ABG analyzer can be used to guide clinical care before the laboratory results become available.