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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
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Minimum level of Beta Hcg detected by radioimmunoassay is :
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The correct answer is  * Radioimmunoassay (RIA) -- It using I125 ido hCG antibodies. It is more sensitive and can detect b subunit of hCG upto 0.002 IU/mL in the serum. It can detect pregnancy as early as 8-9 days after ovulation (day of blastocyst implantation). Radio receptor assay gives highest sensitivity of 0.001 IU/mL in the serum. RIAs are quantitative, so can be used for determining the doubling time of hCG (ectopic pregnancy monitoring). RIAs require 3-4 hours to perform. Reference : D C dutta's Textbook of Obstetrics 7th edition page no 67