Family History Warranting CBC and CMP Testing
A family history of hematologic disorders (anemia, bleeding disorders, hemoglobinopathies), hereditary liver disease, renal disease, or colorectal cancer should prompt ordering of CBC and CMP to screen for inherited conditions that impact morbidity and mortality.
Hematologic Conditions Requiring CBC
Hereditary Anemias and Hemoglobinopathies
- Family history of anemia, particularly in first-degree relatives, warrants CBC testing to screen for hereditary conditions such as thalassemia, sickle cell disease, or hereditary spherocytosis 1.
- A family history of hemoglobinopathies (sickle cell disease, thalassemia) requires CBC evaluation, as these are common hereditary disorders that can cause significant morbidity if undiagnosed 2, 3.
- History of chronic transfusion requirements in family members suggests hereditary anemia requiring CBC assessment 2.
Bleeding and Clotting Disorders
- Family history of excessive bleeding (hemophilia, von Willebrand disease) or excessive clotting (thrombophilias, recurrent DVT/PE) necessitates CBC to evaluate platelet counts and baseline hematologic parameters 1.
- A positive family history of bleeding disorders should include CBC with manual differential and platelet count assessment 1.
- History of unexplained bruising, petechiae, or bleeding complications in relatives warrants CBC evaluation 1.
Bone Marrow Failure Syndromes
- Family history suggesting inherited bone marrow failure syndromes (Diamond-Blackfan anemia, dyskeratosis congenita, Fanconi anemia) requires CBC monitoring 1.
- Children with family history of leukemia-predisposing conditions should have CBC with manual differential and reticulocyte count 1.
Metabolic and Systemic Conditions Requiring CMP
Hereditary Liver Disease
- Family history of heritable liver disease (hemochromatosis, Wilson disease, alpha-1 antitrypsin deficiency) warrants CMP to assess liver function tests and screen for early hepatic involvement 1.
- A family history of chronic liver disease or cirrhosis requires baseline CMP evaluation 1.
Renal Disease
- Family history of renal disease, particularly early-onset kidney failure, necessitates CMP to evaluate creatinine and electrolytes 1.
- History of polycystic kidney disease or hereditary nephritis in relatives requires CMP monitoring 1.
Metabolic Disorders
- Family history of diabetes mellitus should prompt CMP to assess glucose and screen for early metabolic dysfunction 1.
- History of hyperlipidemia or early cardiovascular disease in first-degree relatives warrants CMP evaluation 1.
Cancer Predisposition Syndromes
Colorectal Cancer
- Significant family history of colorectal carcinoma (one first-degree relative <50 years or two first-degree relatives at any age) requires CBC to screen for iron deficiency anemia from occult bleeding 1.
- This family history pattern necessitates CMP to establish baseline liver and renal function before potential colonoscopy 1.
Hematologic Malignancies
- Family history of leukemia or myelodysplastic syndrome warrants CBC with manual differential to establish baseline and monitor for early cytopenias 1, 4.
- Children with family history of leukemia-predisposing conditions require CBC every 3-12 months depending on risk stratification 1.
Specific Clinical Scenarios
Preoperative Assessment
- Family history of anemia or bleeding disorders in patients undergoing surgery requires preoperative CBC 1.
- Family history of liver disease in surgical candidates necessitates preoperative CMP 1.
Medication Monitoring
- Family history of heritable liver disease in patients requiring hepatotoxic medications (methotrexate, statins) mandates baseline and ongoing CBC and CMP monitoring 1.
- Patients with family history of bone marrow disorders starting immunosuppressive therapy require baseline CBC 1.
Critical Pitfalls to Avoid
- Do not dismiss family history as sufficient explanation without establishing baseline values—even with known hereditary conditions, CBC and CMP provide essential baseline data for future comparison 1, 4.
- Do not delay testing in children with positive family history of hematologic malignancies—early detection through CBC monitoring can identify pre-leukemic states requiring intervention 1.
- Do not overlook iron deficiency anemia in patients with family history of colorectal cancer—this may represent occult malignancy requiring urgent evaluation 1.
- Ensure manual differential is performed, not just automated CBC, particularly when family history suggests hereditary blood disorders, as automated counts may miss dysplastic changes or abnormal cell morphology 1, 4.