What are the guidelines for ordering phlebotomy (blood draw)?

How to Order Phlebotomy

For therapeutic phlebotomy in hemochromatosis, order weekly removal of 400-500 mL of blood with pre-procedure hemoglobin/hematocrit monitoring, continuing until serum ferritin reaches 50-100 μg/L. 1

Therapeutic Phlebotomy Protocol (Hemochromatosis/Iron Overload)

Indications for Ordering

• Order therapeutic phlebotomy for patients with serum ferritin ≥300 μg/L in men or ≥200 μg/L in women with confirmed hemochromatosis 2, 3
• C282Y homozygotes with transferrin saturation >45% and elevated ferritin should proceed directly to treatment 2, 3
• Patients with evidence of end-organ damage (liver disease, cardiac dysfunction, diabetes) require immediate initiation 1, 3

Ordering Specifications

Volume and Frequency:

• Order removal of 400-500 mL (one unit) of blood per session 1, 4
• Schedule weekly or twice weekly initially, as tolerated 1, 4
• Each unit removes approximately 200-250 mg of iron 1, 2

Pre-Procedure Requirements:

• Mandate hemoglobin/hematocrit measurement before each session 1, 2
• Postpone if hemoglobin <12 g/dL; discontinue if <11 g/dL 2, 4
• Do not allow hematocrit/hemoglobin to drop >20% from baseline 1, 4, 3

Monitoring Orders

During Induction Phase:

• Order serum ferritin every 10-12 phlebotomies (approximately every 3 months) 1, 2
• When ferritin approaches 200 μg/L, increase monitoring frequency to every 1-2 sessions 4, 3
• Continue until ferritin reaches 50-100 μg/L target 1, 2

Baseline Assessment Orders:

• Transferrin saturation to confirm iron overload (>45% indicates true overload) 2
• Liver function tests (ALT, AST, bilirubin) 2
• Complete blood count with platelets 2
• Consider liver biopsy if ferritin >1000 μg/L with elevated transaminases and platelets <200,000 2

Maintenance Phase Orders

• After reaching target ferritin, order phlebotomy 2-6 times per year to maintain ferritin 50-100 μg/L 1, 4
• Monitor ferritin and transferrin saturation every 6 months 4
• Some patients may not require maintenance; monitor and reinitiate when ferritin rises above normal 1

Diagnostic Phlebotomy (Standard Blood Draw)

Order of Draw Protocol

Follow this specific sequence to prevent cross-contamination between tubes: 5

1. Blood culture/sterile tubes first 5
2. Plain tubes/gel separator tubes second 5
3. Tubes containing additives last 5

This order prevents additive contamination from previous tubes that causes erroneous results, and remains critical despite modern materials 5.

Volume Considerations

• Minimize blood loss by consolidating test orders - ordering multiple tests per draw reduces overdraw by up to 80% compared to single-test draws 6
• Specify small-volume tubes when appropriate, particularly for pediatric patients and ICU patients 1
• Blood drawn from central venous catheters has 254% overdraw compared to 168% for arterial lines and 143% for peripheral IV 6

Safety Requirements

• Ensure proper skin preparation with chlorhexidine in alcohol or equivalent 1
• Use single-use holders and sterile collection tubes to prevent bloodborne pathogen transmission 1, 7
• Provide emergency equipment (bed, oxygen, drug cart) in phlebotomy areas for vasovagal reactions 7
• Avoid antecubital fossa nerve pathways to prevent permanent nerve injury 7

Special Populations

ICU Patients

• Implement bundled blood conservation strategies including small-volume tubes, closed sampling devices, and decision tools showing required volumes 1
• These interventions reduce blood loss by approximately 70% (22.7 mL/day reduction) 1
• Order blood conservation devices that return flush blood to patients, reducing loss by 25% 1

Pediatric Patients

• Patients <10 kg have significantly greater blood loss per kg per day 6
• Use microsample collection tubes 1
• Consolidate phlebotomy orders aggressively to minimize total draws 6

Cirrhotic Patients

• Phlebotomy can be performed even with advanced fibrosis or cirrhosis 1
• Order continued HCC screening every 6 months despite successful iron depletion, as HCC accounts for 30% of hemochromatosis deaths 1, 2, 3
• Ensure adequate hydration before and after treatment 1

Common Pitfalls to Avoid

• Never order phlebotomy without pre-procedure hemoglobin check - this risks severe anemia 1, 2
• Do not continue phlebotomy if ferritin falls below target range, as iron deficiency should be avoided 1
• Avoid ordering single tests when multiple tests can be consolidated - this dramatically increases blood waste 6
• Do not ignore order of draw even with modern equipment - contamination still occurs under non-ideal conditions 5
• Interrupt therapeutic phlebotomy during acute illnesses causing volume depletion 2

Patient Instructions to Include

• Adequate hydration before and after phlebotomy 1
• Avoid vigorous physical activity for 24 hours post-procedure 1
• Avoid iron supplements and iron-fortified foods 2, 4, 3
• Limit vitamin C to ≤500 mg/day (enhances iron absorption) 2, 4
• Restrict or eliminate alcohol, especially if cirrhotic 2, 4