In a reported lab result showing a pH of 7.42 and a bicarbonate of 24 mmol/L, which value is most likely erroneous?

In this case, the bicarbonate level of 24 mmol/L indicates a normal metabolic acid-base status, as the typical reference range for bicarbonate is usually around 22 to 28 mmol/L. The pH of 7.42 is also within the normal range (7.35 to 7.45), suggesting that the acid-base balance is stabilized. Given that the pH and bicarbonate values correlate well with each other, it’s likely that both are accurate.

However, total carbon dioxide (TCO2) is calculated using bicarbonate levels but may include contributions from carbonic acid and dissolved CO2, which could lead to discrepancies if the bicarbonate level is accurate but other mechanisms affecting carbon dioxide levels are not accounted for or are miscalculated.

On the other hand, sodium (Na) and potassium (K) levels, while important for overall metabolism, do not have a direct correlation with acid-base balance in the way that bicarbonate and pH do. Their roles in body function are critical, but they are less likely to be involved in errors related to the acid-base status reflected by the pH and bicarbonate.

Therefore, TCO2 is the value most likely to be erroneous because it can sometimes present errors stemming