Question 63

EDTA tubes should be drawn first for a capillary collection.

In capillary collections, the first tube drawn should be an EDTA tube. This helps to prevent contamination of the sample with other additives and ensures accurate results for hematological tests.

A) EDTA

EDTA tubes are the preferred choice for the first draw in capillary collections because they contain an anticoagulant that preserves the integrity of the blood sample for hematological analysis. By drawing EDTA first, the risk of contamination from other additives in subsequent tubes is minimized, leading to more reliable test results.

B) Lithium heparin

Lithium heparin is an anticoagulant used in some tests, but it should not be drawn first in a capillary collection. Drawing this tube first can lead to contamination and affect the results of tests that require EDTA, which is crucial for accurate hematological assessments.

C) Nonadditive

Nonadditive tubes do not contain any anticoagulants or preservatives, making them unsuitable for the first draw in a capillary collection. If drawn first, they could alter the sample’s composition, potentially skewing the results of tests that are sensitive to such changes.

D) Sodium fluoride

Sodium fluoride is primarily used for glucose testing and should not be the first tube drawn. If drawn first, it can interfere with tests requiring EDTA, compromising the reliability of hematological analyses.

Conclusion

EDTA is definitively the correct choice for the first draw in a capillary collection due to its anticoagulant properties that preserve sample integrity. All other options are incorrect because they either risk contamination or are not suitable for initial blood collection, which could lead to inaccurate test results.