PT  - JOURNAL ARTICLE
AU  - Ben Cranfield
AU  - Minjoung Monica Koo
AU  - Gary A. Abel
AU  - Ruth Swann
AU  - Sean McPhail
AU  - Gregory Rubin
AU  - Georgios Lyratzopoulos
TI  - Primary care blood tests before cancer diagnosis: National Cancer Diagnosis Audit data
AID  - 10.3399/BJGP.2022.0265
DP  - 2022 Sep 13
TA  - British Journal of General Practice
PG  - BJGP.2022.0265
4099  - http://bjgp.org/content/early/2022/09/13/BJGP.2022.0265.short
4100  - http://bjgp.org/content/early/2022/09/13/BJGP.2022.0265.full
AB  - 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&amp;amp;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&amp;amp;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&amp;lt;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.