What additive is present in the Black top tube?

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Multiple Choice

What additive is present in the Black top tube?

Black top tubes used for erythrocyte sedimentation rate (ESR) testing contain 3.8% sodium citrate. This higher citrate concentration chelates calcium to prevent clotting, which is essential for letting the red cells settle by gravity in the Westergren method while preserving the sample’s sedimentation properties. In contrast, 3.2% sodium citrate is used in blue-top tubes for standard coagulation studies like PT and aPTT, sodium heparin is used in green-top tubes for plasma chemistry tests, and potassium EDTA is used in lavender-top tubes for complete blood counts. So the additive in the Black top tube is 3.8% sodium citrate.

Black top tubes used for erythrocyte sedimentation rate (ESR) testing contain 3.8% sodium citrate. This higher citrate concentration chelates calcium to prevent clotting, which is essential for letting the red cells settle by gravity in the Westergren method while preserving the sample’s sedimentation properties. In contrast, 3.2% sodium citrate is used in blue-top tubes for standard coagulation studies like PT and aPTT, sodium heparin is used in green-top tubes for plasma chemistry tests, and potassium EDTA is used in lavender-top tubes for complete blood counts. So the additive in the Black top tube is 3.8% sodium citrate.

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