Enter the times of the first and second measurements and the HCG levels at these times into the calculator to determine the HCG doubling time.

## Hcg Doubling Formula

The following formula is used to calculate the HCG doubling time.

DT = (t2 - t1) / log2(HCG2 / HCG1)

Variables:

- DT is the HCG doubling time (hours)
- t1 is the time of the first measurement (hours)
- t2 is the time of the second measurement (hours)
- HCG1 is the HCG level at the first measurement (mIU/mL)
- HCG2 is the HCG level at the second measurement (mIU/mL)

To calculate the HCG doubling time, subtract the time of the first measurement from the time of the second measurement. Then, divide the HCG level at the second measurement by the HCG level at the first measurement and take the base 2 logarithm of the result. Finally, divide the first result by the second result to get the HCG doubling time.

## What is a Hcg Doubling?

HCG doubling refers to the process where the levels of the hormone human chorionic gonadotropin (HCG) double approximately every 48 to 72 hours during the early stages of pregnancy. This hormone is produced by the placenta after implantation and its rapid increase is often used as an early indicator of pregnancy. The rate of HCG doubling can be used to estimate the age of the fetus and to monitor the health of the pregnancy, with slower rates potentially indicating problems such as miscarriage or ectopic pregnancy.

## How to Calculate Hcg Doubling?

The following steps outline how to calculate the HCG Doubling Time.

- First, determine the time of the first measurement (t1) in hours.
- Next, determine the time of the second measurement (t2) in hours.
- Next, determine the HCG level at the first measurement (HCG1) in mIU/mL.
- Next, determine the HCG level at the second measurement (HCG2) in mIU/mL.
- Next, calculate the numerator of the formula: (t2 – t1).
- Next, calculate the denominator of the formula: log2(HCG2 / HCG1).
- Finally, calculate the HCG Doubling Time using the formula: DT = (t2 – t1) / log2(HCG2 / HCG1).
- After inserting the variables and calculating the result, check your answer with the calculator above.

**Example Problem : **

Use the following variables as an example problem to test your knowledge.

t1: time of the first measurement (hours) = 6

t2: time of the second measurement (hours) = 12

HCG1: HCG level at the first measurement (mIU/mL) = 100

HCG2: HCG level at the second measurement (mIU/mL) = 400