From the Guidelines
Blood tests required to test for lymphoma include a complete blood count, routine blood chemistry, lactate dehydrogenase, β2-microglobulin, and uric acid, as well as screening tests for human immunodeficiency virus (HIV) and hepatitis B and C. These tests are essential for initial staging and risk assessment, as treatment substantially depends on the stage of the disease 1. The complete blood count evaluates white blood cells, red blood cells, and platelets, which may be abnormal in lymphoma.
- Routine blood chemistry assesses organ function, particularly liver and kidneys, which can be affected by lymphoma.
- Lactate dehydrogenase is often elevated in lymphoma and indicates tissue damage and tumor burden.
- β2-microglobulin levels correlate with tumor burden and prognosis. Additional tests may include serum protein electrophoresis to detect abnormal proteins and immunoglobulin levels 1. However, blood tests alone cannot diagnose lymphoma; a tissue biopsy is always required for definitive diagnosis, with blood tests serving primarily as supportive evidence and baseline measurements before treatment. The staging is carried out according to the Ann Arbor classification system, with mention of bulky disease >5 cm when appropriate 1. For prognostic purposes, a ‘Follicular Lymphoma-specific International Prognostic Index’ (FLIPI) has been established, which incorporates β2-microglobulin, diameter of largest lymph node, bone marrow involvement, and haemoglobin level 1.
From the Research
Blood Tests for Lymphoma
- There is no direct evidence in the provided studies that specifies the exact blood tests required to diagnose lymphoma 2, 3.
- However, it can be inferred that a complete blood count (CBC) may be used as part of the diagnostic process, as it is mentioned in the context of evaluating patients with cancer 3.
- Liver function tests (LFTs) are also mentioned as part of the evaluation process for cancer patients, but their specific relevance to lymphoma diagnosis is not clear 3.
- It is worth noting that an open lymph node biopsy is preferred for diagnosis of lymphoma, and the Lugano classification system incorporates symptoms and the extent of the disease as shown on positron emission tomography/computed tomography to stage lymphoma 2.
Limitations of Blood Tests
- The provided studies suggest that routine preoperative screening tests, including CBC and LFTs, may be of low yield in evaluating patients with cancer 3.
- The positive predictive values of preoperative CBC, LFTs, and chest X-ray for occult metastasis are relatively low, ranging from 1.1% to 1.5% 3.
- Therefore, it is possible that blood tests may not be sufficient to diagnose lymphoma, and other diagnostic methods such as biopsy and imaging tests may be necessary 2.