Hyperkalemia is a potentially fatal condition found most often in pati

Inference questions can be a pain in the butt, just because there may or may not be much structure to the argument. Ultimately, all we're trying to do is find four wrong answers that aren't supported by the passage. But that can be tricky, because sometimes it's hard to really make sense of the passage before moving on to the answer choices.

In this particular question, we're not directly asked to explain or identify a discrepancy, but it seems like we have a discrepancy in this passage: despite the fact that doctors prefer treatments to prevent hyperkalemia, kidney transplant recipients are not monitored for hyperkalemia... why not? Here's what we know:

• Hyperkalemia is found most often in patients on kidney dialysis--patients who have lost over 80% of their kidney function.
• Hyperkalemia is potentially fatal and causes pain, severely erratic pulse, and tissue swelling throughout the body.
• Hyperkalemia stems from extremely high levels of potassium in the blood.
• In an emergency, hyperkalemia can be treated with an injection of calcium chloride.
• Since calcium chloride destroys surrounding tissues if it escapes from a vein, doctors overwhelmingly prefer preventative treatments for hyperkalemia. In other words, doctors prefer to prevent the condition rather than letting it develop and then having to treat it with calcium chloride in an emergency. We can infer that doctors would want to monitor patients who are likely to develop hyperkalemia in order to provide preventative treatments and avoid using calcium chloride.
• However, recipients of a donated kidney are NOT monitored for hyperkalemia after a successful kidney transplant.

At first, this might seem like a discrepancy. Kidney transplant recipients clearly have had kidney problems, so wouldn't it be better to monitor those patients for hyperkalemia rather than waiting until the condition develops and then having to use calcium chloride in an emergency? But if those recipients are actually NOT likely to develop hyperkalemia, then this information makes sense. So, which of the choices can properly be inferred based on what we know?

(A) We are told that hyperkalemia is found most often in patients on kidney dialysis, but that does not necessarily mean that most patients on kidney dialysis have hyperkalemia or high levels of potassium in their blood. In other words, patients on kidney dialysis are more likely to have hyperkalemia, but we don't know exactly how likely those patients are to have the condition. (A) can be eliminated.

(B) Hyperkalemia is found most often in patients who have lost over 80% of their kidney function. As explained for choice (A), this does not necessarily mean that those patients are likely to have hyperkalemia or the associated symptoms. (B) can be eliminated.

(C) Calcium chloride can be used to treat hyperkalemia in an emergency, but that does not necessarily mean that levels of calcium chloride in the blood have anything to do with the development of the condition. Thus, we cannot infer that the kidneys play a role in maintaining adequate levels of calcium chloride in the blood, and (C) can be eliminated.

(D) As explained for choices (A) and (B), we don't know exactly how likely it is for patients with kidney failure to have hyperkalemia. If most patients with 80% kidney failure develop hyperkalemia, it is certainly possible that patients with only 50% kidney failure are also likely to develop the condition, but we don't know one way or the other. So choice (D) can be eliminated.

(E) Hyperkalemia stems from extremely high levels of potassium in the blood and is found most often in patients who have lost over 80% of their kidney function. This suggests that kidneys play a role in keeping potassium levels in the blood from getting too high. Thus, choice (E) is the best answer.