Therapeutic phlebotomy is a medical procedure involving the measured removal of blood from a patient’s body to treat specific health conditions. This process is distinct from routine blood donation or small diagnostic blood draws. Performed under a physician’s prescription, the explicit goal is to correct an imbalance within the patient’s blood components. The treatment works by actively reducing excessively high levels of specific elements, such as iron or red blood cells, which can otherwise damage organs and tissues. This targeted approach is often the most effective method for managing the symptoms and complications of certain chronic disorders.
Medical Conditions Requiring Blood Removal
Therapeutic phlebotomy is the primary treatment for conditions characterized by an unhealthy excess of components in the bloodstream. Hereditary hemochromatosis is a common example, where a genetic disorder causes the body to absorb too much iron, leading to iron overload. Since the body lacks a major mechanism for excreting excess iron, the procedure removes iron-rich red blood cells.
Removing blood stimulates the bone marrow to produce new red blood cells, which pulls iron from the body’s storage protein, ferritin, to create new hemoglobin. Repeatedly lowering total body iron stores reduces serum ferritin levels, reversing the accumulation that can damage the heart, liver, and pancreas. The typical target goal is 50 micrograms per liter (\(\mu\)g/L) or less.
For patients with Polycythemia Vera (PV), the procedure addresses the bone marrow’s overproduction of red blood cells, which makes the blood excessively thick or viscous. This increased viscosity raises the risk of severe complications like heart attack, stroke, and blood clots. The goal of phlebotomy in PV is to rapidly normalize the red blood cell mass by lowering the hematocrit level, the proportion of blood volume occupied by red blood cells. Maintaining the hematocrit below 45% is the standard treatment target to reduce the risk of thrombotic events.
In Porphyria Cutanea Tarda (PCT), phlebotomy reduces hepatic iron stores, which are central to the disease’s pathology. Excess iron inhibits a liver enzyme, leading to the accumulation of light-sensitive porphyrins that cause severe skin blistering upon sun exposure. Iron depletion via phlebotomy removes this inhibitory factor, ultimately resolving the skin condition.
The Therapeutic Phlebotomy Process
The therapeutic phlebotomy procedure is performed in a medically supervised environment, such as a specialized clinic, physician’s office, or hospital unit. The process closely resembles a standard blood donation, beginning with the patient seated comfortably in a reclining chair. A trained healthcare professional, often a nurse or phlebotomist, checks the patient’s vital signs before starting the procedure.
A large-bore needle is inserted into a prominent vein, typically in the arm, and is connected to sterile tubing that directs the blood into a specialized collection bag. The volume of blood removed in a single session is usually standardized to one unit, approximately 450 to 500 milliliters.
The actual draw time is typically short, often lasting less than 15 minutes, though the entire appointment may take up to an hour for preparation and monitoring. The prescribed frequency varies significantly depending on the underlying condition and the patient’s current blood levels, requiring a personalized treatment schedule. Patients in the initial, or induction, phase of treatment may require phlebotomy once or twice a week, while a maintenance phase often reduces the frequency to every few months.
Patient Preparation and Recovery
Patient preparation is an important step to minimize the risk of side effects during the procedure. Patients are strongly encouraged to drink extra fluids in the 24 hours leading up to the appointment to help maintain their blood volume. Eating a light, substantial meal approximately one hour before the draw is also recommended to prevent low blood sugar.
During and immediately after the procedure, the healthcare team monitors the patient for potential adverse reactions. The most common side effects are mild, including temporary lightheadedness, dizziness, or faintness, which are often related to the temporary drop in blood volume. Bruising or minor bleeding at the needle insertion site is also a frequent occurrence.
Following the procedure, patients are usually asked to rest for 15 to 30 minutes and are encouraged to continue drinking fluids to rapidly replenish the fluid portion of the blood that was removed. For the next 24 hours, patients should avoid strenuous exercise or heavy lifting that could strain the circulatory system or the venipuncture site. The body quickly replaces the plasma volume within a few hours, while the red blood cells gradually regenerate over several weeks.