Unit Converter
Convert between conventional and SI units for testosterone, estradiol, prolactin, and other lab values. Includes weight, volume, and HCG reconstitution conversions.
Total Testosterone
Common Lab Unit Conversions
| Lab Value | Conventional | SI | Factor |
|---|---|---|---|
| Total Testosterone | ng/dL | nmol/L | x 0.0347 |
| Free Testosterone | pg/mL | pmol/L | x 3.467 |
| Estradiol (E2) | pg/mL | pmol/L | x 3.671 |
| Prolactin | ng/mL | mIU/L | x 21.2 |
| Progesterone | ng/mL | nmol/L | x 3.18 |
| DHEA-S | mcg/dL | umol/L | x 0.02714 |
| Glucose | mg/dL | mmol/L | x 0.0555 |
Understanding IU (International Units)
International Units (IU) measure biological activity rather than weight. One IU of a substance represents the amount needed to produce a specific biological effect. This means the conversion between IU and milligrams is different for every substance, because each has different potency.
For HCG, the IU measurement tells you the biological potency of the medication. When you reconstitute HCG with bacteriostatic water, the concentration (IU per mL) depends on how much water you add. For example, 5,000 IU in 1 mL gives you 5,000 IU/mL, but the same 5,000 IU in 2 mL gives you 2,500 IU/mL. The dose in IU stays the same; only the volume you inject changes.
Insulin syringes are marked in "units" — which for U-100 syringes means 100 units per 1 mL. This makes measuring small volumes much easier. If you need to inject 0.1 mL, that's 10 units on a U-100 syringe. The unit markings on insulin syringes are not the same as IU for other medications — they're a volume measurement.
Frequently Asked Questions
Why do US and UK labs use different units?+
The US primarily uses conventional units (ng/dL, pg/mL, mg/dL), while most of the world uses SI units (nmol/L, pmol/L, mmol/L). This is a historical convention — the SI system was adopted internationally in the 1970s, but the US medical system largely stayed with conventional units. Both measure the same thing, just with different scales.
Are these conversion factors exact?+
Yes — these are standard conversion factors used by clinical laboratories worldwide. They're based on the molecular weight of each substance. For example, testosterone has a molecular weight of 288.42 g/mol, which gives the 0.0347 conversion factor (1/28.842).
How do I convert HCG IU to syringe units?+
First, figure out your concentration: divide the total IU in the vial by the mL of water you reconstituted with. Then divide your target dose (IU) by that concentration to get the volume in mL. Multiply the mL by 100 to get U-100 insulin syringe units. This calculator handles all of that for common concentrations.
What's the difference between U-100 and U-40 syringes?+
U-100 syringes have 100 unit markings per 1 mL — each unit mark equals 0.01 mL. U-40 syringes have 40 unit markings per 1 mL — each unit mark equals 0.025 mL. U-100 syringes are far more common and offer more precise measurements for small volumes. If you're using insulin syringes for non-insulin medications, you almost certainly want U-100.
Can I use these conversions for bloodwork results?+
Yes — these are the same conversion factors used by laboratories. If your results are in nmol/L and you want ng/dL (or vice versa), this tool gives you the same conversion your doctor would use. Just make sure you select the correct lab value (testosterone, estradiol, etc.) since each has a different conversion factor.
Related Tools
Doseline provides informational tools only. It is not a medical device and does not provide medical advice. Always consult a qualified healthcare provider.
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