Test, don't guess: what your bloods can and can't say about your hormones

My mantra is test, don't guess. After twenty-two years and twenty thousand patients, I've never regretted looking properly. But testing only helps if the right test is taken at the right time and read in the right context, and that's where most people come unstuck.

Timing changes the answer

Several of the hormones people most want measured swing dramatically across a cycle. Progesterone drawn in the first week of a cycle will be low in absolutely everyone, including women who ovulate perfectly. Measured about seven days after ovulation, it tells you something meaningful.

Oestradiol, LH and FSH are similarly cycle-dependent and are usually most interpretable in the early follicular phase. Thyroid function and iron studies are less time-critical, though iron studies are affected by recent illness or inflammation and are best repeated rather than trusted from one sample taken while you had a cold.

If you're going to the trouble of testing, it's worth a two-minute conversation about when.

"Normal" is a population, not a person

A reference range is built from a large sample of people. It describes where most results fall. It does not describe where you function best, and it certainly doesn't mean the bottom of the range is equivalent to the middle of it.

This matters most with ferritin and thyroid function, where results at the low end of "normal" often sit alongside real symptoms: fatigue, hair shedding, cold intolerance, low mood. A result inside the range is not automatically a result to ignore, and equally, a result slightly outside it is not automatically a diagnosis. Context decides.

What I look at, and why

For women coming to me about cycles, energy or preparing to conceive, a typical starting picture includes:

• A full blood count and iron studies, including ferritin
• Thyroid function, including TSH, and antibodies where indicated
• Vitamin D and vitamin B12
• Cycle-timed reproductive hormones, where the question calls for them
• Metabolic markers such as fasting glucose and insulin where the history suggests it

The point isn't a longer list. It's a list chosen to answer a specific question you actually have.

Working alongside your doctor, not instead

Naturopathic care at Origia sits beside medical care. If a result needs a specialist, I say so, and here I can walk down the corridor and say so in person. If you're under the care of a fertility specialist or an obstetrician, I want what I do to fit with their plan rather than run parallel to it.

That's the whole reason I'm in this building.

What to do with a result you don't understand

Bring it in. Bring the older ones too, because a trend over three years is far more informative than a single snapshot. Understanding your own results is not a specialist skill you have to be born with. It's just something nobody has taken the time to explain.

This article is general information and isn't a substitute for advice about your own situation.