Serum Protein and Hemoglobin Abnormalities
Know serum protein electrophoresis patterns: albumin, alpha-1 (alpha-1 antitrypsin), alpha-2 (haptoglobin, ceruloplasmin), beta (transferrin, complement), and gamma (immunoglobulins). A monoclonal spike in gamma suggests a plasma cell dyscrasia; confirm with immunofixation and free light chain ratio. Polyclonal increases suggest inflammation or infection.
Understand nephrotic versus nephritic protein patterns, and the significance of low albumin (liver disease, malnutrition, protein loss). Alpha-1 antitrypsin deficiency shows a low alpha-1 band; haptoglobin falls in hemolysis.
Hemoglobin: know hemoglobin electrophoresis and HPLC patterns for sickle cell disease (HbS), thalassemias (elevated HbA2 and HbF in beta-thalassemia trait), and hemoglobin variants that interfere with HbA1c measurement. Understand the difference between iron deficiency anemia (low ferritin, high TIBC) and anemia of chronic disease (low TIBC, normal/high ferritin).
Worked example: an IgG kappa monoclonal protein with suppressed other immunoglobulins and a free light chain ratio of 10 suggests myeloma; order bone marrow and skeletal survey.
Trap: interpreting a small monoclonal band as benign without checking the free light chain ratio and clinical context-MGUS versus malignancy requires risk stratification.