The conditions behind it fall into a few categories, and a complete blood count (CBC), liver tests, renal function, and the clinical context often narrow the category
I'm just wondering what evidence you have for this
doi: 10.1016/S0022-3999(01)00315-4 Summary Keywords Sensewear armband, myalgic encephalomyelitis/chronic fatigue syndrome, vitamin B12 nasal drops, vitamin B12 serum concentration, RAND 36 questionnaire Citation van Campen CLMC, Riepma K and Visser FC (2019) Open Trial of Vitamin B12 Nasal Drops in Adults With Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Comparison of Responders and Non-Responders
The secondary antibodies used are as follows: Goat Anti-Mouse IgG H&L (Alexa Fluor 488) (Abcam, ab150113), Goat Anti-Mouse IgG H&L (Alexa Fluor 647) (Abcam, ab150115), Goat Anti-Rabbit IgG H&L (Alexa Fluor 488) (Abcam, ab150077), Donkey Anti-Rabbit IgG H&L (Alexa Fluor 647) (Abcam, ab150075)