@article {CranfieldBJGP.2022.0265, author = {Ben Cranfield and Minjoung Monica Koo and Gary A. Abel and Ruth Swann and Sean McPhail and Gregory Rubin and Georgios Lyratzopoulos}, title = {Primary care blood tests before cancer diagnosis: National Cancer Diagnosis Audit data}, elocation-id = {BJGP.2022.0265}, year = {2022}, doi = {10.3399/BJGP.2022.0265}, publisher = {Royal College of General Practitioners}, abstract = {Background: Blood tests can support the diagnostic process but how often they are used in cancer patients is unclear. Aim: To explore use of common blood tests before cancer diagnosis in primary care. Design and setting: English National Cancer Diagnosis Audit data on 39,752 cancer patients diagnosed in 2018. Methods: We assessed common blood test use (full blood count (FBC), urea and electrolytes (U\&Es), and liver function tests (LFTs)), related variation by patient and symptom group, and associations with the primary care and the diagnostic intervals (PCI, DI). Results: At least one common blood test was used in 41\% of cancer patients. Among tested patients, FBC was used in 95\%, U\&Es in 88\% and LFTs in 74\%) Blood testing was less common in women (adjusted odds ratio (aOR) vs men: 0.92, 95\%CI: 0.87-0.98) and non-white patients (0.89, 0.82-0.97 vs white) and more common in older patients (1.12, 1.06-1.18 for 70+ vs 50-69 years). Test use varied greatly by cancer-site, (melanoma: 2\%, leukaemia 84\%). Fewer patients presenting with alarm symptoms alone were tested (24\%) than those with non-alarm symptoms alone (50\%). Median PCI and DI were longer in tested than non-tested patients (PCI: 10 vs 0; DI: 49 vs 32 days, respectively, p\<0.001 for both), including among tested patients with alarm symptoms (PCI: 4 vs 0; DI: 41 vs 22). Conclusions: Two-fifths of patients subsequently diagnosed with cancer have primary care blood tests. Given variable test use, research is needed on the clinical context in which blood tests are ordered.}, issn = {0960-1643}, URL = {https://bjgp.org/content/early/2022/09/13/BJGP.2022.0265}, eprint = {https://bjgp.org/content/early/2022/09/13/BJGP.2022.0265.full.pdf}, journal = {British Journal of General Practice} }