Which initial investigations should be conducted in a patient suspecte

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Initial investigations for a patient suspected of having Non-Hodgkin Lymphoma (NHL) include:

Urgent full blood count (FBC) to assess for haematological abnormalities such as leukemia, especially if lymphadenopathy is generalized .
Consideration of excision biopsy of the largest accessible lymph node as the first diagnostic procedure to obtain tissue for histological diagnosis .
If excision biopsy is not feasible or the surgical risk is high, a needle core biopsy with the maximum number of cores of the largest possible calibre should be performed .
Pathology departments should conserve tissue from needle core biopsies for further analysis if needed .
Fluorescence in situ hybridisation (FISH) testing for MYC rearrangement and other genetic markers may be considered after histological diagnosis, particularly in high-grade B-cell lymphomas .
Imaging with FDG-PET-CT is used for staging after diagnosis but may be considered early if it will alter management .
Chest X-ray may be arranged urgently in adults with supraclavicular or persistent cervical lymphadenopathy to exclude lung cancer, tuberculosis, or sarcoidosis .
Referral for specialist assessment should be made urgently (within 2 weeks for adults) if unexplained lymphadenopathy or splenomegaly is present, especially with systemic symptoms such as fever, night sweats, weight loss, or pruritus .

Which initial investigations should be conducted in a patient suspected of having Non-Hodgkin Lymphoma?