Question 31

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

A tuberculin skin test must be read within 24 hours of administration to ensure accurate interpretation of the results.

A) of

This option is correct because it directly indicates the time frame within which the skin test results should be evaluated after the test is administered. The phrase "within 24 hrs of administration" clearly communicates the required timing for reading the test.

B) since

This option is incorrect as "since" implies a continuous duration from a past point to the present, which does not accurately convey the immediacy required for reading the tuberculin skin test. It does not fit the context of specifying a time limit for reading the test results.

C) as

The use of "as" in this context is inappropriate because it suggests a simultaneous occurrence rather than a specified time frame for reading the test results. It fails to convey the urgency of the 24-hour reading requirement.

D) from

While "from" could imply a starting point for counting time, it does not effectively communicate the necessity of reading the test results within a specific time frame. It lacks the clarity of the term "of," which is essential for understanding the required timing.

Conclusion

The phrase "within 24 hrs of administration" is crucial for ensuring that the tuberculin skin test is read at the correct time to obtain valid results. Options B, C, and D do not provide the clear and specific timeframe necessary for accurate interpretation, making A the only suitable choice.