The Blood Work Your GP Probably Isn’t Ordering (And Why You Should Ask)

When you go to your GP and ask for blood work, you’ll typically get what’s called a “standard panel.” In Australia, that usually means a full blood count (FBC), basic metabolic panel, liver and kidney function, maybe a lipid panel, and if you’re lucky, a TSH for thyroid and a fasting glucose.

That’s maybe 20% of the useful information your blood can tell you.

There are markers that can reveal early insulin resistance years before diabetes shows up on standard tests. Markers that distinguish between a thyroid that’s producing hormones and a thyroid whose hormones are actually reaching your cells. Markers that explain why your energy is tanked, your hair is falling out, and your mood has gone sideways – even when the standard panel comes back “all clear.”

The problem isn’t that these tests don’t exist. It’s that they’re not part of the default order.

These are the tests worth running before you accept ‘perimenopause’ as an explanation.

1. Full Thyroid Panel

What most GPs order: TSH only. What you should ask for: TSH, Free T4, Free T3, Reverse T3, TPO antibodies, Thyroglobulin antibodies.

TSH alone tells you whether your pituitary is yelling at your thyroid to work harder. That’s useful, but it doesn’t tell you whether your thyroid is responding, whether the hormones it makes are converting properly, or whether your immune system is attacking it.

Free T4 is what your thyroid directly produces. Free T3 is the active form your cells actually use (T4 converts to T3). If T4 is normal but T3 is low, you have a conversion problem that TSH alone won’t reveal.

Reverse T3 is what your body produces when it’s under stress – it’s an inactive form of T3 that blocks the real T3 from working. High reverse T3 with “normal” TSH is one of the most commonly missed patterns.

TPO and thyroglobulin antibodies tell you whether you have Hashimoto’s – the autoimmune form of thyroid disease. You can have elevated antibodies for years before TSH becomes abnormal. Catching it early changes the management approach entirely.

2. Ferritin

What it measures: Your iron storage, not just circulating iron. Why it matters: A serum iron test can come back normal while your ferritin is on the floor. Ferritin below 50 is associated with fatigue, hair loss, restless legs, poor exercise tolerance, and brain fog – even though most labs won’t flag it until it drops below 12–15.

If you’re a menstruating woman, your ferritin should be checked at least annually. If you have heavy periods (common with endometriosis and fibroids), check it more often.

3. Fasting Insulin

What it measures: How hard your pancreas is working to keep your blood sugar in check. Why it matters: This is the test that catches insulin resistance early – sometimes a decade before fasting glucose becomes abnormal. By the time your glucose is elevated, your pancreas has been overproducing insulin for years trying to compensate.

Fasting insulin above 8-10 mU/L with symptoms (weight gain around the middle, fatigue after eating, sugar cravings, difficulty losing weight) suggests insulin resistance is developing. This connects to PCOS, inflammation, cardiovascular risk, and hormone metabolism.

Most GPs don’t order this unless you’re already flagged as pre-diabetic or diabetic. You often need to specifically request it.

4. Vitamin D (25-Hydroxyvitamin D)

What it measures: Your vitamin D storage. Why it matters: Vitamin D is involved in immune regulation, mood, bone health, and thyroid function. Deficiency is associated with autoimmune conditions (including Hashimoto’s), depression, and increased inflammation.

In Australia, despite the sunshine, vitamin D deficiency is surprisingly common – particularly if you wear sunscreen (as you should), work indoors, or have darker skin. A level below 75 nmol/L is considered insufficient by the Endocrine Society, even though some labs set the lower limit at 50 or even 30.

5. Active B12 (Holotranscobalamin) or Serum B12

What it measures: Your B12 status. Why it matters: Standard serum B12 tests measure total B12 in your blood, but not all of it is in a usable form. Active B12 (holotranscobalamin) measures the fraction that your cells can actually use, making it a more accurate marker.

B12 deficiency causes fatigue, brain fog, numbness and tingling, mood disturbances, and memory problems. It’s common in people with gut issues (B12 absorption depends on a healthy stomach and small intestine), people on acid-reducing medications, and people with methylation variants.

6. Homocysteine

What it measures: An amino acid that should be efficiently recycled by your body using B12, folate, and B6. Why it matters: Elevated homocysteine is a marker that your methylation pathways aren’t working efficiently. It’s associated with cardiovascular risk, cognitive decline, pregnancy complications, and mood disorders.

Optimal is below 7-8 μmol/L. Many labs set the upper limit of the reference range at 15, which is already associated with increased risk. If homocysteine is high, it points toward B12, folate, or B6 deficiency – or a methylation issue (like an MTHFR variant) that affects how you process these nutrients.

7. High-Sensitivity CRP (hs-CRP)

What it measures: Systemic inflammation. Why it matters: Standard CRP is usually only ordered when infection or acute inflammation is suspected. High-sensitivity CRP detects low-grade chronic inflammation – the kind that simmers in the background driving autoimmune activity, cardiovascular risk, and metabolic dysfunction.

Optimal is below 1.0 mg/L. Above 3.0 is associated with significantly elevated cardiovascular risk. If your hs-CRP is persistently elevated, something is driving inflammation – whether that’s gut permeability, autoimmune activity, insulin resistance, or chronic infection.

8. Zinc (Serum or Plasma)

What it measures: Your zinc status. Why it matters: Zinc is involved in over 300 enzymatic reactions including immune function, thyroid hormone production, DAO enzyme activity (histamine clearance), skin health, and mood regulation.

Zinc deficiency is common in women, especially those with gut issues (zinc is absorbed in the small intestine), those who are vegetarian or vegan, and those with pyroluria (which causes excessive zinc and B6 loss through urine). Symptoms of deficiency include white spots on nails, poor wound healing, skin issues, hair loss, low appetite, and frequent infections.

Serum zinc isn’t a perfect test (it can appear normal even when tissue levels are low), but it’s a starting point.

9. Copper (Serum) and Zinc-to-Copper Ratio

What it measures: Copper levels and the balance between zinc and copper. Why it matters: Copper and zinc compete for absorption, so they need to be assessed together. Elevated copper relative to zinc is associated with anxiety, hormonal issues (copper is estrogen-dependent – as estrogen rises, so does copper), and oxidative stress.

Women on hormonal contraceptives or hormone replacement therapy often have elevated copper. This is rarely tested but can be a significant factor in mood symptoms, histamine issues, and hormonal imbalance.

10. DHEA-S

What it measures: Your main adrenal androgen hormone. Why it matters: DHEA-S reflects adrenal function and can indicate whether chronic stress has depleted your adrenal reserve. Low DHEA-S with symptoms of fatigue, low stress tolerance, and poor recovery is a common pattern in women with chronic health conditions.

It’s also relevant for hormone metabolism – DHEA is a precursor to both estrogen and testosterone. If DHEA-S is tanked, your entire hormonal cascade is working with reduced raw materials.

11. Full Iron Studies (Not Just Ferritin)

What it measures: Serum iron, transferrin, transferrin saturation, and ferritin together. Why they matter together: Ferritin alone tells you about storage, but the full picture includes how much iron is circulating (serum iron), how much transport capacity is available (transferrin), and what percentage of that transport is actually carrying iron (transferrin saturation).

Low transferrin saturation with normal ferritin can indicate early functional iron deficiency. High ferritin with normal iron can indicate inflammation rather than true iron excess (ferritin is an acute-phase reactant — it rises with inflammation regardless of iron status).

12. Fasting Glucose AND HbA1c Together

What they measure: Fasting glucose is a single-moment snapshot. HbA1c reflects your average blood sugar over the past 2-3 months. Why both matter: You can have a normal fasting glucose and an elevated HbA1c (meaning your blood sugar is spiking throughout the day even though it looks fine in the morning). You can also have a normal HbA1c and elevated fasting insulin (meaning your pancreas is working overtime to maintain normal glucose – the pre-pre-diabetes phase).

Testing glucose alone without insulin or HbA1c is like judging a duck by how calm it looks on the surface while ignoring how fast the legs are paddling underneath.

How to ask for these tests

Walk into your appointment prepared. Here are some approaches that work:

“I’ve been experiencing [specific symptoms] and I’d like a more comprehensive panel to investigate. Can we add [specific tests] to the order?”

“I know the standard panel checks the basics, but I’m concerned about [thyroid autoimmunity / insulin resistance / nutrient deficiencies] based on my symptoms. Can we include [specific tests]?”

If your GP says no or that the tests aren’t necessary, you can ask: “Can you please note in my file that I requested these tests and that they were declined?” This is a respectful but firm approach that often shifts the conversation.

In Australia, some of these tests may not be covered by Medicare when ordered by a GP without a specific clinical indication. If that’s the case, you can ask about the out-of-pocket cost (often $20-60 per test) and decide whether it’s worth it. For many women, the cost of a couple of extra tests is far less than years of unexplained symptoms.

You can also request your GP to refer you to a practitioner who orders more comprehensive panels as standard practice.

The free cheat sheet

I’ve created a one-page Blood Work Cheat Sheet that covers all 12 of these markers with optimal ranges and a script for requesting them. It’s designed to save on your phone and take to your next appointment.

[Get the free Blood Work Cheat Sheet →]

Bold Leap provides health education, not medical advice. The tests and ranges discussed here are for educational purposes. Always work with a qualified healthcare provider when ordering and interpreting blood work.