Question 23

A tuberculin skin test should be read within 24 hours of administration.

The correct preposition to complete the sentence is "of." This indicates the relationship between the reading of the test and the administration of the tuberculin.

A) of

This option is correct because "of" properly connects the reading of the test to the point in time when the administration occurred, indicating a specific timeframe within which the test should be assessed.

B) since

This option is incorrect as "since" suggests a duration or a starting point in time, which does not fit the context of needing to read the test within a specified period after administration.

C) as

This option is also incorrect. "As" implies a simultaneous occurrence or a reason, which does not convey the intended meaning of the timeline required for reading the test.

D) from

This option is incorrect as well. "From" indicates a starting point but does not denote the specific timeframe needed to read the test, making it unsuitable in this context.

Conclusion

The choice "of" is the only option that accurately conveys the relationship between the timing of the test reading and its administration. The other options fail to express this connection appropriately, highlighting why they are not suitable in this context.