Biomaterial Database

Dual-isotope separation technique for radioassay of cobalamin. 1979

J F Place

Cobalamin is assayed by a dual-isotope separation method using sodium [125I]iothalamate as a marker. Two systems are used: one in which the incompletely-separated bound fraction is counted and compared with the single-isotope method in which the bound fraction is separated by washing (Phadebas radiosorbent assay); and one in which an aliquot of the free fraction is counted. In the dual-isotope method counting bound fractions, about 97% of the supernatant is removed by pouring from silicone fluid separators. The results for serum samples obtained using dual- and single-isotope methods were similar (between run coefficients of variation 5--7%). Experimental errors were smaller in the dual-isotope method. A factor in the kit standards, presumably the absence of proteins, was found to affect the separation technique, resulting in relatively large experimental errors for standards in the single-isotope method. Washing the solid phase in the single-isotope method apparently resulted in a loss of bound isotope. In the dual-isotope method counting free fractions reasonable precision was obtained (coefficient of variation of serum samples 6.6%) even though only about 56% of the supernatant (free fraction) was counted.

UI	MeSH Term	Description	Entries
D007457	Iodine Radioisotopes	Unstable isotopes of iodine that decay or disintegrate emitting radiation. I atoms with atomic weights 117-139, except I 127, are radioactive iodine isotopes.	Radioisotopes, Iodine
D007483	Iothalamic Acid	A contrast medium in diagnostic radiology with properties similar to those of diatrizoic acid. It is used primarily as its sodium and meglumine (IOTHALAMATE MEGLUMINE) salts.	Iotalamic Acid,Methalamic Acid,Angio-Conray,Conray 420,Iodothalamate,Iothalamate,Iothalamic Acid, Calcium (2:1) Salt,Iothalamic Acid, Monosilver (1+) Salt,Iothalamic Acid, Monosodium Salt,Iothalamic Acid, Monosodium Salt, Dimer,Lopamidol,Sodium Iothalamate,Acid, Iotalamic,Acid, Iothalamic,Acid, Methalamic,Angio Conray,AngioConray,Iothalamate, Sodium
D011852	Radioallergosorbent Test	An in vitro allergen radioimmunoassay in which allergens are coupled to an immunosorbent. The coupled allergens bind the IgE in the sera of patients which in turn binds radioisotope-labeled anti-IMMUNOGLOBULIN E antibodies.	Radioimmunosorbent Assay of Allergens,Allergens Radioimmunosorbent Assay,Allergens Radioimmunosorbent Assays,Radioallergosorbent Tests,Test, Radioallergosorbent,Tests, Radioallergosorbent
D011933	Reagent Kits, Diagnostic	Commercially prepared reagent sets, with accessory devices, containing all of the major components and literature necessary to perform one or more designated diagnostic tests or procedures. They may be for laboratory or personal use.	Diagnostic Reagent Kits,Diagnostic Reagents and Test Kits,Diagnostic Test Kits,In Vitro Diagnostic Device,In Vitro Diagnostic Devices,In Vitro Diagnostic Medical Device,In Vitro Diagnostic Medical Devices,Kits, Diagnostic Reagent,Diagnostic Reagent Kit,Diagnostic Test Kit,Kit, Diagnostic Reagent,Kit, Diagnostic Test,Kits, Diagnostic Test,Reagent Kit, Diagnostic,Test Kit, Diagnostic,Test Kits, Diagnostic
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D014805	Vitamin B 12	A cobalt-containing coordination compound produced by intestinal micro-organisms and found also in soil and water. Higher plants do not concentrate vitamin B 12 from the soil and so are a poor source of the substance as compared with animal tissues. INTRINSIC FACTOR is important for the assimilation of vitamin B 12.	Cobalamin,Cyanocobalamin,Cobalamins,Eritron,Vitamin B12,B 12, Vitamin,B12, Vitamin