What labs are recommended for an older adult with a history of immunosuppression or previous cancers suspected of having lymphoma, presenting with symptoms like weight loss, fever, or night sweats?

Laboratory Workup for Suspected Lymphoma in Older Adults with Immunosuppression or Prior Malignancy

For older adults with immunosuppression or previous cancers presenting with B symptoms (fever, night sweats, weight loss >10% body weight), obtain a complete blood count with differential, comprehensive metabolic panel including LDH and albumin, ESR, HIV/hepatitis B/hepatitis C screening, and cardiac function testing (LVEF) immediately, as these labs guide both diagnosis and treatment planning. 1, 2

Essential Laboratory Tests

Core Hematologic and Chemistry Panel

• Complete blood count with differential and platelets to assess for cytopenias, atypical lymphocytosis, or leukemia 1, 2, 3
• Erythrocyte sedimentation rate (ESR) as an inflammatory marker and prognostic indicator 1
• Serum lactate dehydrogenase (LDH) - elevated levels strongly correlate with tumor burden and prognosis 1, 2, 3
• Serum albumin - low levels indicate advanced disease and poor prognosis 1
• Beta-2 microglobulin - prognostic marker for disease burden 1, 3
• Uric acid - assess tumor lysis risk before treatment 1, 3
• Comprehensive liver and renal function tests to evaluate organ involvement and treatment tolerance 1

Mandatory Infectious Disease Screening

HIV, hepatitis B, and hepatitis C testing must be performed in all suspected lymphoma cases, as these infections significantly impact prognosis, treatment selection, and risk stratification. 1, 2 This is particularly critical in immunosuppressed patients who have higher rates of these infections and lymphoma development. 2

Cardiac Assessment

Left ventricular ejection fraction (LVEF) evaluation is required for all patients being considered for curative-intent treatment, as anthracycline-based chemotherapy (standard for most lymphomas) carries cardiotoxicity risk. 1 This is especially important in older adults with potential pre-existing cardiac disease.

Risk Stratification Laboratory Work

Prognostic Scoring

• Calculate the International Prognostic Index (IPI) using age, LDH, performance status, stage, and number of extranodal sites 1
• For follicular lymphoma specifically, calculate FLIPI or FLIPI-2 incorporating beta-2 microglobulin, diameter of largest lymph node, bone marrow involvement, and hemoglobin 1

Bone Marrow Evaluation

Bone marrow aspirate and biopsy should be performed in fit elderly patients to assess marrow involvement, which affects staging and treatment decisions. 1, 2 However, this can be deferred in vulnerable or terminally ill patients if peripheral blood counts are normal and the result would not change management. 1

Important exception: In Hodgkin lymphoma patients undergoing PET/CT staging, routine bone marrow biopsy is not required if the PET scan is negative or shows homogenous bone marrow uptake. 1 The bone marrow may be assumed involved if PET shows multifocal (≥3) skeletal lesions. 1

Additional Considerations for High-Risk Populations

Immunosuppressed Patients

• These patients require comprehensive geriatric assessment (CGA) to stratify as fit, vulnerable, or terminally ill, which determines treatment intensity and which labs are truly necessary 1, 4
• Flow cytometry of peripheral blood should be obtained if absolute lymphocyte count is elevated, as chronic lymphocytic leukemia is common in this population 4

Patients with Prior Malignancy

• Consider screening for secondary malignancies as whole-body imaging may reveal incidental findings in 3.1% of cases 5
• Previous chemotherapy or radiation exposure increases risk of therapy-related lymphomas

Critical Pitfalls to Avoid

Never delay tissue diagnosis to obtain laboratory results - excisional lymph node biopsy remains the gold standard and should proceed immediately in patients with persistent painless lymphadenopathy >2-4 weeks with B symptoms. 2, 3 Fine-needle aspiration alone is insufficient except when combined with immunohistochemistry and reviewed by an expert hematopathologist. 1

Never administer empiric antibiotics or corticosteroids before tissue diagnosis, as these mask histologic findings and delay definitive diagnosis. 3