6.1 Precautions for Patients with Medical Conditions
Key Takeaways
- The arm on the side of a mastectomy with lymph node dissection is avoided because of lymphedema and infection risk.
- An arteriovenous fistula or graft is never used for venipuncture and the access arm is avoided entirely.
- Draw from the opposite arm whenever an IV is infusing; drawing above an active IV is never acceptable.
- Patients on anticoagulants require extended direct pressure and observation until hemostasis is confirmed.
- A burned, scarred, edematous, or paralyzed limb is avoided because the specimen and the patient are both at risk.
6.1 Precautions for Patients with Medical Conditions
Quick Answer: DTP task 3.2 requires taking precautions for patients with medical conditions (e.g., mastectomy, IV, bleeding disorders). Each condition maps to one rule: mastectomy side — avoid; AV fistula or graft — never; active IV — opposite arm; anticoagulated — extended pressure; edema, burns, scars, paralysis — avoid.
Mastectomy and Lymph Node Dissection
After a mastectomy with axillary lymph node dissection, lymphatic drainage on that side is impaired. Two risks follow:
- Lymphedema. Fluid accumulates in the arm. The tissue is edematous, so a specimen drawn there is diluted with interstitial fluid and the results are unreliable.
- Infection. With lymphatic clearance compromised, a puncture that would be trivial on the other arm can seed a cellulitis that is difficult to treat.
The rule: avoid venipuncture, capillary puncture, tourniquet application, and blood pressure measurement on the affected side.
| Situation | Action |
|---|---|
| Unilateral mastectomy | Use the unaffected arm — no order needed |
| Bilateral mastectomy | Obtain a physician order specifying the acceptable site; hand or foot veins may be authorized |
| Mastectomy more than 2 years ago | Facility policies differ; many now permit the affected arm with a physician order. Follow your facility policy and confirm rather than assuming |
| Lumpectomy without node dissection | Generally not restricted, but ask the patient and confirm |
[!IMPORTANT] Ask the patient, and believe them. Many patients know their restriction better than the chart reflects it, and many wear an alert bracelet. "Which arm do they usually use?" is a fast, respectful question that catches this and several other restrictions at once.
Vascular Access Devices
Arteriovenous Fistula and Graft
A hemodialysis patient's AV fistula (a surgically created artery-to-vein connection) or AV graft (a synthetic conduit) is a lifeline. Puncturing it risks thrombosis, infection, aneurysm, and loss of the access, potentially requiring a new surgical access and interim catheter dialysis.
The rule is absolute: never perform venipuncture in a fistula or graft, and avoid the entire access arm. Also avoid the tourniquet and blood pressure cuff on that arm. If both arms have access, consult nursing — dialysis nursing staff typically draw from the access as part of a treatment.
You can usually feel a fistula: a palpable vibration called a thrill and an audible bruit.
Central Lines, Ports, and PICCs
Drawing from central venous catheters, implanted ports, and peripherally inserted central catheters is generally outside the phlebotomy scope and is performed by specially trained nursing staff. These lines require sterile technique, a specific discard volume, and flushing protocols.
Active Intravenous Lines
The dominant risk is dilution: drawing near an infusing line collects IV fluid rather than blood, producing dramatically distorted results.
Priority order:
- Opposite arm. Always the first choice.
- Below the IV on the same arm, only if unavoidable — infusion stopped for at least 2 minutes, tourniquet applied below the IV site, puncture distal to the site, first 5 mL discarded, then collect.
- Never above an active IV. There is no protocol that makes this acceptable.
- Document that the draw was performed below an IV and note what was infusing.
[!WARNING] A phlebotomist never stops, restarts, disconnects, or adjusts an IV. Request the pause from licensed nursing and wait for confirmation that it has been done.
The signature of IV contamination is internal inconsistency: a glucose in the hundreds or thousands alongside a diluted sodium and potassium in a patient who looks well.
Bleeding Disorders and Anticoagulant Therapy
DTP task 4.1 covers protocols for patients on anticoagulant therapy or with clotting deficiencies. These patients can be drawn — the modification is in hemostasis, not in site selection.
| Category | Examples | Modification |
|---|---|---|
| Anticoagulants | Warfarin, apixaban, rivaroxaban, heparin, enoxaparin | Extended direct pressure, commonly 5 minutes or more; observe until hemostasis confirmed |
| Antiplatelet agents | Aspirin, clopidogrel | Extended pressure; expect bruising even with good technique |
| Clotting factor deficiencies | Hemophilia A and B, von Willebrand disease | Extended pressure; notify nursing; smallest adequate gauge; avoid the basilic vein |
| Thrombocytopenia | Chemotherapy, ITP, marrow disease | Extended pressure; avoid vigorous tourniquet pressure, which causes petechiae |
| Liver disease | Cirrhosis with impaired factor synthesis | Extended pressure |
Practical modifications for all of them:
- Use the most superficial, best-anchored vein available — the median cubital rather than a mobile, deep vessel.
- Minimize tourniquet time and pressure.
- Do not use a spot bandage alone. A self-adherent wrap over gauze holds pressure better.
- Stay with the patient until bleeding stops, and instruct against heavy lifting with that arm.
[!IMPORTANT] A patient on warfarin is not a contraindication to venipuncture. The exam distractor is refusing the draw. The correct answer is always to proceed with appropriate technique and extended hemostasis.
Sites and Limbs to Avoid Entirely
| Condition | Why it is avoided |
|---|---|
| Edema | Interstitial fluid dilutes the specimen; tissue is fragile and heals poorly |
| Burns and scars | Impaired circulation, increased infection risk, difficult vein access, and pain |
| Hematoma | Specimen contaminated with hemolyzed extravascular blood; draw below the hematoma if the limb must be used |
| Sclerosed or thrombosed veins | Hardened, cord-like vessels give poor flow and unreliable specimens |
| Paralyzed limb | Impaired circulation and, critically, the patient cannot feel a nerve injury and report it |
| Cast or splint | Access and circulation both compromised |
| Tattoos | Avoid recent tattoos; pigment and inflammation raise infection risk and obscure the vein |
| Foot and ankle veins | Require a physician order because of thrombosis risk, especially in diabetic and cardiac patients |
A patient with a left-sided mastectomy and axillary node dissection has an intravenous line infusing in the right forearm. What is the appropriate approach?
A hemodialysis patient has an arteriovenous fistula in the left forearm, identifiable by a palpable thrill. Where may blood be drawn?
A patient taking warfarin requires a routine PT/INR. What modification does the anticoagulation require?