2.2 Collection Methods and Adverse Reactions

2.2 Collection Methods and Adverse Reactions

Quick Answer: Whole blood is collected by antecubital venipuncture into a closed bag holding anticoagulant-preservative for a 450 mL or 500 mL (±10%) draw after a two-step chlorhexidine or iodine arm prep and diversion of the first aliquot into a sample pouch. Every unit carries a unique ISBT-128 donation identification number (DIN). Apheresis removes platelets, plasma, red cells, or a concurrent combination and returns the remainder with citrate anticoagulant. Vasovagal reactions are the most common donor events, especially in young first-time donors. Citrate toxicity is the signature apheresis reaction (perioral tingling) and is treated by slowing the return and giving calcium. Donor-chair events are not recipient transfusion reactions.

Once 21 CFR 630.10 says the donor is eligible, the collection itself has its own safety engineering. The BB outline splits this into collection methods and adverse reactions because a technically perfect history still produces a discarded unit — or an injured donor — if the arm prep, volume, or reaction response is wrong.

Whole-blood venipuncture

The usual site is a large antecubital vein. Staff inspect both arms (the physical assessment already required a clean phlebotomy site) and apply a validated skin-disinfection method. AABB Technical Manual methods and FDA-cleared prep kits use either a two-step povidone-iodine or iodine-tincture scrub-and-paint or a chlorhexidine gluconate / isopropyl alcohol prep (commonly a 30-second scrub and a 30-second dry). Iodine-allergic donors need the chlorhexidine (or other validated iodine-free) method. The site is not repalpated with a non-sterile finger after the prep. The goal is to cut the bacterial load that lives in skin appendages — Staphylococcus species are the classic platelet contaminants — before the needle enters.

A diversion pouch (integral sample pouch) receives the first aliquot of blood, typically on the order of 30–50 mL, before the primary bag fills. That first volume is the blood most likely to contain the skin plug and surface organisms. Diversion, together with arm prep and later bacterial detection on platelets, is why modern platelet contamination rates are far below pre-diversion practice. The diverted volume also supplies the tubes for ABO/Rh, antibody screen, and infectious-disease markers so the primary bag is not entered for sampling.

The primary bag already contains a measured anticoagulant-preservative (CPD, CP2D, or CPDA-1; additive solutions attach later). A 450 mL collection is paired with about 63 mL of CPDA-1; a 500 mL collection with about 70 mL. The Circular of Information describes allogeneic whole blood as 450 mL (±10%) or 500 mL (±10%). AABB Standards limit total collection, including samples, to 10.5 mL/kg. A 50 kg donor at the regulatory weight floor cannot safely give a full 500 mL plus a large sample panel. Low-volume red-cell units (for a 450 mL bag system, collections of 300–404 mL) may still be labeled as Red Blood Cells, Low Volume; plasma and platelets are not made from those under-collected bags because the anticoagulant ratio is wrong.

Collection should be brisk. A draw that stretches much beyond about 10–15 minutes allows early clot activation. Red cells may still be kept; platelets and plasma are typically not manufactured from a prolonged collection. The bag is mixed gently during the draw so anticoagulant contacts incoming blood. After the needle is withdrawn, staff apply firm pressure, instruct the donor not to lift with that arm, and observe the donor in a refreshment area before release.

Unique DIN and closed-system identity

Every collection receives a unique ISBT-128 donation identification number (DIN). The DIN identifies the collecting facility, a flag character, the year, and a serial number for that donation event. All components split from that collection — red cells, plasma, platelets, cryoprecipitate — carry the same DIN plus a product-code suffix. The DIN is how lookback, market withdrawal, and a recipient-trace investigation find every bag from that sitting. It is not the donor’s name, not the unit ABO, and not a hospital accession number. Handwriting a name on the bag instead of applying the DIN is a labeling failure, not a workaround.

Apheresis methods

Apheresis uses an automated separator (centrifugation or, less often, filtration) and a sterile disposable kit. Whole blood leaves the donor, citrate anticoagulant is added in a controlled ratio, the target component is retained, and the remainder is returned. Common procedures:

Concurrent collections are attractive for inventory but they still count against red-cell-loss and protein clocks. Granulocyte apheresis is a special stimulated collection and is treated with special donations, not routine community inventory.

Because citrate travels back to the donor in the return line, ionized calcium falls during apheresis. That is expected physiology, not a machine malfunction. Whole-blood collection does not return citrate, which is why perioral tingling during a standard 500 mL draw should make you think nerve irritation or hyperventilation, not classic citrate toxicity.

Adverse reactions — recognize, treat, then decide about next time

Vasovagal reactions are the most common donor adverse events. They are a neural (not hypovolemic-first) response: anxiety, pain, or the sudden drop in venous return triggers a paradoxical increase in vagal tone. The donor becomes pale, diaphoretic, nauseated, and bradycardic; vision tunnels; syncope may follow. They cluster in young donors, first-time donors, and low-weight donors, and they are more likely with whole blood than with plasma-only apheresis. Immediate first aid: stop or pause the collection, get the donor supine with legs elevated (Trendelenburg or a reclining chair), loosen tight clothing, apply cold compresses, and give reassurance. Do not sit a nauseated donor upright “to drink juice” while still gray. After recovery, observe longer than a routine donor. Delayed syncope — fainting after the donor has left the chair, sometimes in the parking lot — is the driving-risk variant. First-time and young donors deserve a longer post-donation observation precisely because delayed syncope is over-represented in that group. A donor with recurrent or severe vasovagal syncope, especially with injury, may be deferred from future whole-blood donation or steered to a smaller-volume apheresis product after physician review.

Citrate toxicity is an apheresis-return reaction. Falling ionized calcium produces perioral tingling or numbness, a metallic taste, a sense of vibration, and — if ignored — carpopedal spasm, tetany, or, rarely, cardiac arrhythmia. Treatment is mechanical and simple: slow or pause the return, ask the donor to cough or converse (which also lets you reassess), and give oral calcium (calcium carbonate tablets are standard on apheresis floors). Severe cases need the procedure stopped and medical evaluation. This is not a hemolytic transfusion reaction, not TRALI, and not treated with diphenhydramine as first-line therapy. Whole-blood donors do not get classic citrate toxicity because they do not receive a citrate return.

Hematoma is blood leaking into subcutaneous tissue after the needle leaves the lumen or punctures the back wall. The site swells and discolors. Stop the collection if the bag is still filling, withdraw the needle, and apply firm, prolonged pressure with the arm extended (not tightly bent, which can worsen a hidden leak). Cold packs early, then later warm packs, and written aftercare. A large or expanding hematoma, numbness, or a cool hand needs escalation.

Nerve injury presents as an electric-shock, shooting pain, or persistent paresthesia at needle insertion — not a dull pressure ache. Remove the needle immediately. Continuing the draw because “the bag is almost full” is how a transient irritation becomes a months-long injury. Document, arrange follow-up, and do not reuse that site until the donor is asymptomatic and a physician has cleared further phlebotomy.

Arterial puncture is uncommon but distinctive: bright red, pulsatile, high-pressure flow, and a rapidly filling bag. Remove the needle and apply firm pressure for at least 10 minutes, then a pressure dressing. Check distal pulses. Do not collect from that arm again that day. Future donation from that arm waits until the site has fully healed and staff are confident the artery was not aneurysmally injured. The unit, if already collected, is not a routine red-cell product — follow SOP; arterial collections are typically discarded.

Air embolism is rare in modern closed, air-detector-equipped apheresis sets and integral whole-blood bags. If it is suspected (sudden respiratory distress, chest pain, cough during return), stop the return, clamp the line, place the donor left-side down / Trendelenburg (Durant maneuver) to keep residual air out of the left ventricular outflow, give oxygen, and activate emergency response. Do not treat this as a faint.

Iron depletion is the delayed, cumulative cost of frequent donation, especially in premenopausal women and double-red-cell donors. Hemoglobin can still pass the same-day screen while ferritin is falling. Centers increasingly offer ferritin testing and iron replacement counseling; low hemoglobin at the next visit is a temporary deferral, not a moral failing. Teach donors the 56-day and 112-day clocks exist in part to let red-cell mass recover.

Donor reactions are not recipient transfusion reactions

A donor who becomes hypotensive in the chair is having a donor adverse reaction. A patient who becomes hypotensive 15 minutes into a red-cell transfusion is having a recipient transfusion reaction until proven otherwise (AHTR, bacterial contamination, anaphylaxis, TACO, TRALI). The workups, the forms, the unit-return rules, and the clerical check are different. Exam stems that mention “the donor reports perioral tingling during the return cycle” want citrate management, not a DAT. Stems that mention “the recipient’s urine turned red” want a transfusion-reaction workup, not Trendelenburg.

First aid, documentation, and future deferral

Every reaction is documented on the collection record and, when the event meets the center’s seriousness criteria, in the quality system. Give written aftercare. Tell the donor whom to call if symptoms worsen. Consider future-donation limits when: syncope caused injury or is recurrent; arterial puncture or nerve injury has not fully resolved; the donor cannot tolerate citrate even after return-rate adjustment; or hemoglobin/ferritin trajectory shows unsafe iron loss. A single uncomplicated vasovagal faint in a first-time 19-year-old is usually observation and education, not a lifetime deferral. A seizure-like convulsive syncope with laceration is a physician decision before the next appointment is booked.