Hi, friend is getting a blood test soon (fbe, tsh, b12/folate and iron studies) him being a regular cannabis consumer, will the test detect marijuana?

Probably not: Since the tests that you listed were not drug tests for thc canabinoids then they will not directly show marihuana use. However, abnormalities in tests may illicit further history from your friends practitioner. Most urine drug tests do test for thc use and the tests may stay positive for over a month.

Unlikely: Thc metabolites are stored in body fats and excreted through urine. So it is unlikely that thc would be detected in blood test. But cannabis use would be detected in urine test. If he should be testers for employment etc., best he stop or reduce cannabis. Best regards, dr. Catherine shaw.

Only if they look: Tests are focused. They take technician time and expensive materials. Cannabis would not be detected on the tests you mention. However, if they choose to look they could find it. In the US most states require people sign a waver authorizing any such drug test.