Alicia's average on her five tests is 88 points. The score range for each test is 0 points to 100 points, inclusive. What is the lowest possible score that Alicia could have earned on one of the five tests?
If Alicia's average score on her five tests is 88 points, then the sum of her scores must be $88 \times 5 = 440$ points. If she earned   100 points on four of the tests, then she could have earned a score as low as $\boxed{40\text{ points}}$ on the other test.