Examples:

• The valproic acid test is considered a safe procedure.
• This is an acid test of our European spiritual values.
• The acid test is this: Can the teacher produce enlightenment?
• The current crisis is an acid test, and we must understand its full significance.
• And for this acid test, what's the plan? Clearly, we should start in small scale
• But the acid test is always going to be, how would sharks really behave in the context of these patterns and shapes.
• Political will means regarding climate issues as an acid test for Europe and for a different type of globalisation.
• A valproic acid test measures the amount of valproic acid, which is an anticonvulsant medicine,in a blood sample.
• The Middle East conflict could therefore become the acid test of the efficiency of European Middle East policy.
• The introduction of the single currency, the euro, at the dawn of the twenty-first century, is an acid test we cannot evade.