Patient Care Decision Making and Consultation
Patient care decision making and consultation
Laboratory hematology is a consultative discipline: the right test, at the right time, interpreted in the right clinical context. Start with pretest probability - a young woman with fatigue is more likely to have iron deficiency than a rare hemoglobinopathy, and a patient with isolated aPTT prolongation and bleeding after dental extraction needs factor assays, not a thrombophilia panel. Avoid reflexive panels: an "anemia workup" without a reticulocyte count, ferritin, or smear is low value. Every test carries cost, turnaround time, and the potential for false positives that generate further testing.
Transfusion decisions are clinical. Restrictive thresholds (hemoglobin 7–8 g/dL in stable inpatients; 8 g/dL in cardiac surgery or symptomatic coronary disease) reduce exposure without harm, and single-unit transfusion with reassessment is standard. Platelet thresholds are <10 × 10^9/L for prophylaxis, <20 × 10^9/L for most procedures, and higher for central nervous system or ocular surgery; avoid prophylactic platelets in TTP and HIT. Plasma is for coagulopathy with bleeding or before procedures, not volume expansion or isolated mild INR elevation; cryoprecipitate is used for fibrinogen <100–150 mg/dL. Apheresis is indicated for TTP (plasma exchange), severe sickle cell crisis (red cell exchange), hyperleukocytosis, and selected autoimmune diseases.
Communication matters: call critical values promptly (blasts, new pancytopenia, schistocytes, INR >5), document the conversation, and recommend the next step. A consultant who explains why a test should be repeated prevents more harm than one who orders everything.
Trap: treating a number rather than a patient - a stable asymptomatic patient with hemoglobin 7.5 g/dL may not need transfusion, while an actively bleeding patient with 9 g/dL may.
Rule of thumb: before ordering, ask whether the result will change management; if not, discuss with the clinical team first.