The in-vitro procedures include radioimmunoassay of hormones, red cell survival test, estimation of red cell mass and vitamin B12 absorption studies. By far Radioimmunoassay exceeds all other procedures in the in-vitro Division. The most common label used in this division is I-125 which may be attached to an analyte as in radioimmunoassay (RIA) or to a reagent (antibody) as in imminoradiometric assay (IRMA). Assays commonly done are the following: Serum total T4, total T3, free T4, free T3, serum TSH, serum prolactin, serum follicular stimulating hormone, serum leutinizing hormone, serum testosterones, serum Progesterone, serum Estradiol, serum Cortisol, serum Calcitonin, etc. The RBC survival test is done by Cr-51 autologous RBC (labeled to patients own blood). Estimation of VitB12 malabsorption is done by the dual isotope method (Co-57, Co-58). The most common tumor marker assay done at the institute is serum Thyroglobulin, Alpha feto protein, Carcino embryonic antigen, prostate specific antigen and hepatitis B surface antigen. Establishment of assay for determination of other tumor markers is in progress. Anti thyroid antibodies TPOAb and TGAb is estimated to evaluate for autoimmune thyroid problems. Automated RIA has been introduced for RIA and IRMA of different hormones. Also automated CLIA (ADVIA Centaur XPT and IMMULITE 2000 XPi Immunoassay systems) is now in operation for estimating different hormones. The countrywide screening for neonatal hypothyroidism is an ongoing large scale research project performed in the screening laboratory of RIA division. Thesis works of M.Phil / M.D students of Nuclear Medicine and different departments of BSMMU is conducted in the In-vitro Division.