What blood work is recommended to check for cancer?

Blood Tests for Cancer Screening and Detection

There is no single blood test specifically designed to screen for all types of cancer in asymptomatic individuals without risk factors. Blood tests should be ordered based on specific cancer risk factors, symptoms, or as part of age-appropriate cancer screening protocols 1, 2.

General Approach to Cancer-Related Blood Work

• Complete Blood Count (CBC) is not recommended as a routine screening test for cancer in asymptomatic individuals, as there is insufficient evidence supporting its use for early detection of most cancers 1, 3
• Tumor markers should be ordered selectively based on specific clinical suspicions, not as general cancer screening tools 1, 2
• Cancer-related blood work should be targeted based on:
  • Age-appropriate screening guidelines
  • Specific symptoms
  • Family history
  • Known genetic predispositions 1, 2

Specific Blood Tests Based on Clinical Context

For Suspected Hematologic Malignancies:

• Complete Blood Count (CBC) with differential when symptoms suggest possible leukemia or lymphoma (unexplained fatigue, easy bruising, recurrent infections, lymphadenopathy) 1, 4
• Lactate dehydrogenase (LDH) may be included as part of tumor lysis syndrome panel when large leukemia burden is suspected 1

For Suspected Germ Cell Tumors:

• Alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin (β-hCG) for suspected germ cell tumors, particularly with mediastinal or retroperitoneal masses 1

For Suspected Prostate Cancer:

• Prostate-specific antigen (PSA) for men aged 55-69 years after shared decision-making discussion about benefits and risks 1, 2
• PSA testing may begin at age 45 for high-risk men (African American men or those with first-degree relatives diagnosed with prostate cancer before age 65) 1, 2

For Suspected Liver Cancer:

• Alpha-fetoprotein (AFP) may be considered for patients with liver masses or risk factors for hepatocellular carcinoma 1

For Suspected Ovarian Cancer:

• CA-125 testing for women with symptoms or findings suggesting possible ovarian cancer (not recommended for general screening) 1

Important Limitations and Considerations

• No blood test can definitively rule out cancer; further investigation is needed when clinical suspicion remains high despite normal blood work 3, 5
• False positives and false negatives occur with all cancer-related blood tests 2, 3
• Blood tests should be interpreted in the clinical context, not in isolation 6, 5
• Abnormal blood test results require appropriate follow-up, which may include imaging studies or tissue sampling 1, 3

Special Populations

• For children with genomic instability disorders (like ataxia-telangiectasia), routine blood work for cancer screening is no longer recommended as there is insufficient evidence supporting early detection benefit 1
• Individuals with known hereditary cancer syndromes may require specialized screening protocols beyond standard blood tests 1

Remember that a comprehensive cancer-related checkup should include not only appropriate laboratory tests but also physical examination focusing on the thyroid, mouth, skin, lymph nodes, and sex-specific examinations 1.