text: if my hcg was 122 on fri. and now 993 today , that is more than doubling right? does it sound like multiples o or do i just have lots of hormones the doubling rule. doctors can also perform quantitative serum beta hcg levels. the measurement is done in miu/ml, and a level above 25 miu/ml usually indicates the presence of a pregnancy. two tests are usually necessary to verify a normal increase, usually 2-3 days apart. the increase in serum hcg can be interactively monitored. below an hcg level of 1,200 miu/ml the hcg usually doubles every 48-72 hours, though a rise of 50-60% is still considered normal. between 1,200 and 6,000 miu/ml serum the hcg usually takes 72-96 hours to double, and above 6,000 miu/ml, the hcg often takes more than four days to double. failure to increase normally may indicate that the pregnancy is not developing well and can be an early sign for a possible miscarriage or an ectopic pregnancy.