A meal before the blood test lowered TSH, and borderline results may flip

The edition in brief

A meta-analysis of 14 studies with paired same-day samples in 1,257 people found TSH was on average 0.80 mIU/L lower after eating than fasting, with larger drops in overt and subclinical hypothyroidism, and no difference in free T4 or free T3; heterogeneity was extreme and certainty low, but the authors suggest borderline hypothyroidism could be misclassified as normal. A study of 37 en bloc bladder resections found flat atypical urothelium extending a mean 4.7 mm and up to about 1 cm beside high-grade papillary urothelial carcinoma, usually clonally related to the tumour and reaching the mucosal margin in 12 of 13 cases; its CK20 and p53 pattern can mimic carcinoma in situ. In 5,233 non-small cell lung cancers, MTAP deletion by sequencing was found in 5.6%, and immunohistochemistry agreed with sequencing in 97.3% of a 105-case subset, performing better at low tumour content. In 89 intravenous leiomyomatoses, HMGA2 was upregulated in 87.5% and rearranged in about half, while MED12 mutation and fumarate hydratase deficiency were rare.