It depends on how easily blood can be drawn and the size of the blood vessel.
What if the procedure is not performed?
High hemoglobin can affect the circulatory system, causing blood clots that may be life-threatening and can increase the risk of heart attack, pulmonary embolism, or stroke. See the doctor immediately if you experience dizziness, difficulty breathing, coughing up blood, fainting, chest pain, and/or pain, swelling, or redness or pain under pressure at the leg. These may be symptoms of thrombosis and must be treated immediately.