Transfusion medicine
Restrictive RBC trigger Hb <7 for most (TRICC). Cardiac surgery ~7.5 (TRICS). ACS may warrant 8–10 (MINT signal). Ortho/CAD historically <8.
Eashwar Somasundaram6 min6 questions5 trials
What the blood bank is testing
Type and screen is a three-day passport, not a personality test. Know what each tube is actually asking.
| Test | What is mixed | What it answers |
|---|---|---|
| ABO — front type | Patient RBCs + reagent anti-A or anti-B | Which A/B antigens sit on the red cell |
| ABO — back type | Patient plasma + reagent RBCs | Which anti-A or anti-B lives in the plasma |
| Rh(D) | Patient RBCs + reagent anti-D | D antigen. Anti-D is not a naturally occurring antibody |
| Antibody screen (T&S) | Patient plasma + screening RBCs + Coombs reagent | Unexpected alloantibodies. 'Active' for 3 days |
| Crossmatch (T&C) | Patient plasma + the donor unit | Final compatibility, performed just before transfusion |
| DAT (direct Coombs) | Patient RBCs + anti-IgG / anti-C3 | Antibody or complement already on the patient's cells |
Red cells and platelets
| Product | What you are holding | When to give it | What to expect |
|---|---|---|---|
| RBCs — 1 U ≈ 330 mL, Hct ~55%. Leukoreduced ± irradiated ± washed (rarely) | Oxygen-carrying hemoglobin | Hb <7 for most (; ). <7.5 in cardiac surgery (). <8 in CAD or orthopedic surgery (). Consider <10 in acute MI (, ). Acute hemorrhage >15% of intravascular volume. AIHA — no strict Hb trigger; transfuse for symptoms. Sickle cell: see that protocol | 1 unit raises Hb ~1 g/dL. In hemorrhage, run over 60–90 min. Otherwise 2–4 h |
| Platelets — 1 U = a 6-pack ≈ 300 mL. Apheresis (one donor) or pooled (many). Leukoreduced ± irradiated | Primary hemostasis | Prophylaxis <10k (); antifibrinolytics if cancer-related thrombocytopenia is refractory. <50k for major bleed, intra/post-op bleed, or prophylaxis before invasive procedures (<30k for many bedside procedures). <100k after bypass, ICH, or ophthalmic surgery (no hard data). ITP: only if life-threatening CNS/GI/GU bleed, often after wet purpura | Check a count at 30–60 min: 1 unit raises platelets ~30k if there is no consumption. Apheresis has not been shown superior to pooled. Platelets do not reverse antiplatelet drugs (PATCH, ). Avoid in TTP/HUS and HIT unless life-threatening bleed |
Plasma, cryoprecipitate, and factors
| Product | Contents / dose | Indications | Limits |
|---|---|---|---|
| FFP — 1 U = 250 mL. Start with 2 U. All coagulation factors, frozen after collection | 2 U ≈ +10% factor activity. Effect lasts <6 h (factor VII half-life). Cannot push INR below ~1.7 | Bleeding from factor deficiency. Acute liver failure: only if bleeding or pre-op. Trauma, DIC, congenital TTP (ADAMTS13). Warfarin: vitamin K > PCC > FFP (). Prophylaxis before bedside procedures if INR >2 is low-quality evidence (:CD012745) | Cirrhosis: treating INR with FFP can increase portal pressure and bleeding (J ). Cryo is preferred for fibrinogen. FFP potentiates heparin via ATIII |
| Cryoprecipitate — 10 U = 150 mL. Factor VIII, XIII, VWF, fibrinogen | 10 U should raise fibrinogen ~85 mg/dL. Fibrinogen half-life 3–5 days | Fibrinogen 50–100 mg/dL → 10 U; <50 → 20 U. Massive transfusion with low fibrinogen or abnormal ROTEM/TEG. Complex cardiac surgery (). Postpartum hemorrhage (). DIC, uremia if DDAVP fails, FVIII deficiency, VWD. Cirrhosis: fibrinogen <100–120 or suspected dysfibrinogenemia | Last-resort FVIII or VWF replacement — use concentrates first |
| Coagulation factors — VIII, IX, rFVIIa, ATIII; 3-factor PCC (II+IX+X, Profilnine); 4-factor PCC (II+VII+IX+X, Kcentra); FEIBA; VWF/FVIII (Humate-P) | Targeted replacement | Factor deficiency or inhibitor. VWD (Humate-P, NovoSeven). VKA reversal (IV vitamin K first; PCC > FFP for severe bleed) | Blood-bank approval required. Allergic reactions and thrombosis |
Antifibrinolytics, albumin, IVIG
Antifibrinolytics are lysine analogs that occupy plasminogen, slow fibrinolysis, and buy hemostasis. Aminocaproic acid (Amicar) and tranexamic acid come topical, oral, and IV.
- Trauma (Health Tech 2013;17:1); postpartum hemorrhage (); cardiac surgery (; J Thor C Surg 2019;157:644); ECMO.
- Cirrhosis when hyperfibrinolysis is suspected. Major orthopedics. Platelet refractoriness from HLA alloimmunization. Closed-space bleeding. Factor-inhibitor states. Ongoing bleed with persistent thrombocytopenia.
Albumin
- 5% is iso-oncotic; 25% is hyperoncotic. Both bags hold 12.5 g albumin and 154 mEq sodium (isotonic).
- 5% when hypovolemic or intravascularly depleted; 25% when you are fluid- or sodium-restricted.
- Cirrhosis: HRS, SBP, large-volume paracentesis. : 4% albumin similar to 0.9% saline when albumin >2 (SAFE, ).
- ARDS: 25% albumin 25 g q8h × 3 days plus a furosemide drip × 3 days improved oxygenation and net negative balance when albumin <2 ().
- Contraindicated in traumatic brain injury.
IVIG
- Polyclonal IgG plus trace plasma contaminants. Dose-adjust for obesity.
- Immunodeficiency if IgG <400. Immunosuppression in ITP, AIHA, post-transfusion purpura, acquired von Willebrand syndrome.
- Neurology: CIDP, myasthenia, Guillain–Barré. Infectious: toxic , Kawasaki.
- Side effects: infusion reactions, aseptic meningitis, hyperosmolar renal tubular injury, thrombosis.