Complications: Signs and Responses
Stop the draw for rapid swelling, shooting nerve pain, bright red pulsing blood, fainting or a seizure; remove the needle, apply pressure and get help as policy requires.
During the draw
| complication | signs | phlebotomist response | source |
|---|---|---|---|
| Hematoma | Swelling or bruising forming at the site | Release the tourniquet, remove the needle at once and apply direct pressure; a cold compress can ease symptoms | Korean guideline 2025; Merck Manual; Hamad Medical Corporation lab guide |
| Accidental arterial puncture | Bright red, pulsing blood, rapid tube filling, fast-forming hematoma | Remove the needle at once; firm pressure for at least 5 minutes or until bleeding stops; notify the supervisor or physician and document | Korean guideline 2025; Hamad Medical Corporation lab guide |
| Nerve injury | Electric-shock-like or intense stabbing pain, tingling, numbness in the arm | Remove the needle immediately; any further attempt at another site, preferably the other arm; refer if symptoms persist | Korean guideline 2025 |
| Vasovagal reaction (fainting, syncope) | Pallor, sweating, dizziness or light-headedness, sighing, slow pulse, vomiting; may lose consciousness | Stop: release the tourniquet, remove the needle; lay the patient flat (or recline) with head lowered, loosen tight clothing, monitor until recovery; call the nurse, physician or emergency code if unresponsive | Korean guideline 2025; Hamad Medical Corporation lab guide; WHO 2010, Table 4.1 (signs, from blood donation) |
| Nausea or vomiting | Patient feels sick to the stomach | Stop the draw; deep slow breaths, cold compress on the forehead; emesis basin | Korean guideline 2025; Hamad Medical Corporation lab guide |
| Seizure | Uncontrolled jerking movements, loss of awareness | Stop at once; lower to the floor or secure in the chair, move objects away, do not restrain, remove gum or food from the mouth, and note how long it lasts for the provider | Korean guideline 2025 |
| Petechiae | Tiny red dots (bleeding into the skin) below the tourniquet | Can follow tourniquet pressure on fragile capillaries, but can also go with low platelets or antiplatelet medicines: report it to the nurse or provider per policy; hold pressure until bleeding stops and notify the physician if bleeding lasts over 5 minutes | MedlinePlus; Rumpel-Leede case report (PMC10405879); Croatian recommendations 2013 |
Preview only. The full sheet also covers: No blood flow: adjustments; Afterward (post-procedure).
Sources
- Chang J, et al. Standards and Practice Guidelines for Venous Blood Collection: Consensus Recommendations from the Korean Society for Laboratory Medicine. Ann Lab Med 2025;45(4):343-357 (PMC12187494) · Annals of Laboratory Medicine via PubMed Central
- WHO Guidelines on Drawing Blood: Best Practices in Phlebotomy (2010); official WHO IRIS PDF, also published as NCBI Bookshelf NBK138650 · World Health Organization
- How To Do Venous Blood Sampling (Merck Manual Professional Edition, procedure page) · Merck & Co., Inc. (Merck Manuals)
- Nikolac N, Supak-Smolcic V, Simundic AM, Celap I. Croatian Society of Medical Biochemistry and Laboratory Medicine: national recommendations for venous blood sampling (based on CLSI H3-A6). Biochem Med 2013;23(3):242-254 (PMC3900082) · Biochemia Medica via PubMed Central
- Rumpel-Leede Phenomenon Following Radial Artery Catheterisation. Eur J Case Rep Intern Med 2023 (PMC10405879): petechiae after tourniquet-like compression with capillary fragility, thrombocytopenia or platelet dysfunction · European Journal of Case Reports in Internal Medicine via PubMed Central
- Bleeding into the skin (Medical Encyclopedia; facts checked only, wording not used) · MedlinePlus, U.S. National Library of Medicine
- Laboratory Guide, Adult Venous Blood Collection: Complications (hematoma, arterial puncture, syncope, nausea, excessive bleeding) · Hamad Medical Corporation, Department of Laboratory Medicine and Pathology
Free Routine Blood Collections practice questions
- Question 1Under CLIA, a laboratory's written labeling procedure must call for the patient's name or a unique identifier and, when appropriate, which other item?
- Question 2Croatian national recommendations allow tubes to be labeled after the draw only if the patient is still seated in front of the phlebotomist. Why?
- Question 3According to MedlinePlus, emergency services should be called when a seizure lasts longer than how long?