Consider the following statements regarding the examination for blood, Singapore

Question 1.15

Consider the following statements regarding the examination for blood:

1. Presumptive tests provide an indication for the presence of biological fluid. They are generally safe, inexpensive, sensitive, quick and easy to perform.
2. The Kastle-Meyer (KM) test for blood is more sensitive but has more false positives as compared to the OBTI test (immuno-chromatographic confirmatory test).
3. The sequence of adding ethanol, KM reagent and hydrogen peroxide during a presumptive test for blood would allow the detection of an oxidising agent such as potassium dichromate.
4. A colour change, from pink to colourless, would indicate a positive KM test result.
5. Some plant materials such as horseradish and root nodules of legumes can give rise to a false-positive result when tested using the KM test.

Which of the following is correct?

1. Statements 1, 2, 3 and 5 are TRUE
2. Statements 2, 3, 4 and 5 are TRUE
3. Statements 1, 3, 4 and 5 are FALSE
4. Statements 2, 3, 4 and 5 are FALSE
5. Statements 1, 2, 3, and 4 are TRUE