Basophilia
BioMG follows French guidelines. Adapt it to the guidelines and the tests available where you practise.
Moderate basophilia (> 0.1 G/L): recheck
Laboratory tests
- FBC with blood film
- TSH (if signs of hypothyroidism)if needednon-French guidelineSigns of hypothyroidism (fatigue, cold intolerance, weight gain, skin infiltration, myxoedema): myxoedema is one of the causes to look for in unexplained persistent basophilia [1].
- CRP (if signs of infection or inflammatory disease)if needednon-French guidelineThe Scottish NHS Highland guide (2024) proposes a blood film, inflammatory markers and TSH in basophilia, noting that reactive causes mostly give very modest elevations, of the order of 0.2 G/L [2]. The 2017 expert consensus does not provide for this test [1].
In 8 weeks
- FBC with blood film (repeat)
Also consider
- Associated leucocytosis? If the blood count also shows leucocytosis, see the page “Neutrophilia, leucocytosis”.
- High platelets? If the blood count also shows thrombocytosis, see the page “Thrombocytosis (platelets > 450 G/L)”.
- High haemoglobin or haematocrit? If the blood count also shows polycythaemia, see the page “Polycythaemia”.
Do not order
- Total IgE “to look for an allergy”: the French laboratory fee schedule (NABM) specifies that it is not an allergy screening test and limits reimbursement to a few indications (polysensitisation, certain parasitic diseases, chronic urticaria, atopic dermatitis, allergic bronchopulmonary aspergillosis, certain immune deficiencies), of which basophilia is not one [3].
Persistent unexplained basophilia or marked basophilia (> 1 G/L)
Laboratory tests
- FBC with blood film
- BCR-ABL transcript (preferably at the haematologist's initiative)if neededUnexplained persistent basophilia, even below the threshold of hyperbasophilia: the consensus recommends testing for BCR-ABL1 on blood [1]; in CML, basophilia is typical [1]. NABM procedure limited to the diagnosis and follow-up of CML [3].
- JAK2 V617F mutation (not in the French laboratory fee schedule; preferably by the haematologist)if needednon-French guidelineUnexplained persistent basophilia without BCR-ABL transcript, especially with polycythaemia, thrombocytosis or splenomegaly: JAK2 V617F is among the recommended blood tests [1].
Sources (10)
- Valent P, Sotlar K, Blatt K, et al. Proposed diagnostic criteria and classification of basophilic leukemias and related disorders. Leukemia. 2017;31(4):788-797.
- NHS Highland (Écosse). Basophilia (Guidelines). TAM (Treatments and Medicines), document TAM615, version 2, relu le 29 janvier 2024 (prochaine révision le 31 janvier 2027).
- Assurance maladie. Nomenclature des actes de biologie médicale (NABM), version 105 : actes 0969 (tryptase), 1035 (transcrit BCR-ABL) et 1200 (IgE totales).
- Riley LK, Rupert J. Evaluation of Patients with Leukocytosis. Am Fam Physician. 2015;92(11):1004-1011.
- Apperley JF, Milojkovic D, Cross NCP, et al. 2025 European LeukemiaNet recommendations for the management of chronic myeloid leukemia. Leukemia. 2025;39(8):1797-1813.
- Feriel J, Depasse F, Geneviève F. How I investigate basophilia in daily practice. Int J Lab Hematol. 2020;42(3):237-245.
- Agence du numérique en santé. Terminologie LAHN (liste des actes innovants hors nomenclature), version 2026-04 : code N417 (JAK2 V617F).
- Smith CJ, Kluck LA, Ruan GJ, Ashrani AA, et al. The differential diagnosis of basophilia in patients undergoing BCR-ABL testing. Am J Hematol. 2020;95(9):E216-E217.
- Gold Coast Health (Queensland, Australie). Neutrophilia: criteria for referral to specialist outpatient services. Mis à jour le 18 juin 2025.
- Hochhaus A, Brioli A, Brümmendorf TH, et al. Chronische Myeloische Leukämie (CML). Leitlinie Onkopedia (DGHO), septembre 2026.