Define hemoconcentration and name tests that can be falsely elevated by it.

Define hemoconcentration and name tests that can be falsely elevated by it.

• A. Hemoconcentration occurs when a tourniquet is left on too long, concentrating blood components; commonly elevates potassium, calcium, total protein, and iron.
• B. Hemoconcentration occurs when a tourniquet is removed quickly.
• C. Hemoconcentration is the same as hemodilution.
• D. Hemoconcentration lowers all analytes.

Answer: (A)

Hemoconcentration is a collection artifact where leaving the tourniquet on too long reduces plasma volume at the draw, concentrating blood components in the sample. This makes certain analytes appear higher than they truly are. The most commonly affected tests are potassium, calcium, total protein, and iron, which can be falsely elevated because the plasma is more concentrated than normal. To prevent this, release the tourniquet as soon as the vein is secured and proceed with the draw, then mix tubes properly. This concept reminds us that not all high readings reflect the patient’s physiology—some come from how the sample was collected. The other statements aren’t accurate: removing the tourniquet quickly doesn’t cause hemoconcentration; hemoconcentration is not the same as hemodilution, and it doesn’t lower all analytes.

Hemoconcentration is a collection artifact where leaving the tourniquet on too long reduces plasma volume at the draw, concentrating blood components in the sample. This makes certain analytes appear higher than they truly are. The most commonly affected tests are potassium, calcium, total protein, and iron, which can be falsely elevated because the plasma is more concentrated than normal.

To prevent this, release the tourniquet as soon as the vein is secured and proceed with the draw, then mix tubes properly. This concept reminds us that not all high readings reflect the patient’s physiology—some come from how the sample was collected.

The other statements aren’t accurate: removing the tourniquet quickly doesn’t cause hemoconcentration; hemoconcentration is not the same as hemodilution, and it doesn’t lower all analytes.