Question 36

Citrate, heparin, EDTA, fluoride

The correct order of collection for blood samples is citrate, heparin, EDTA, and fluoride. This sequence ensures accurate laboratory results by preventing interference from anticoagulants.

A) Citrate, heparin, EDTA, fluoride

This option is correct as it follows the recommended order for blood collection tubes. Citrate is used for coagulation studies, followed by heparin for plasma studies, EDTA for hematology, and fluoride for glucose testing, ensuring that each additive performs its intended function without contamination.

B) Citrate, EDTA, heparin, fluoride

This option is incorrect because it places EDTA before heparin. EDTA is a strong anticoagulant and should not be drawn prior to heparin as this can lead to erroneous results in tests that require heparinized plasma.

C) Fluoride, EDTA, heparin, citrate

This option is incorrect as it begins with fluoride, which is typically used last in the collection order. Starting with fluoride can contaminate samples that require other anticoagulants, compromising the integrity of test results.

D) Fluoride, heparin, EDTA, citrate

This option is also incorrect as it places fluoride at the beginning of the sequence. Fluoride should be the last additive used to avoid interference with the other anticoagulants and to ensure accurate glucose testing.

Conclusion

The correct order of collection is crucial for obtaining accurate laboratory results. Option A is the only choice that adheres to the established protocol for blood sampling, while the other options disrupt the necessary sequence, leading to potential testing errors and compromised sample integrity.