Lab Tests Every Thyroid Patient Needs (Not thyroid lab tests): The Complete List

You Need More than Just Thyroid Lab Tests

It probably won’t come as a surprise but you need to be ordering more than just your typical thyroid lab tests if you are a thyroid patient. 

And that’s exactly what we are going to be talking about today. 

I mentioned in my previous post and video that people with thyroid tunnel vision often feel that their thyroid is the single most important factor in managing their health. 

There is some truth to this statement but you also don’t want to neglect other important because you are hyper-focusing on your thyroid. 

Why do these other tests matter?

Because they give you further information regarding the root cause of your thyroid condition AND for the reasons mentioned below:

• Your thyroid affects almost every cell and tissue in your body. 
• Your thyroid affects OTHER hormone systems and directly leads to hormone imbalances. 
• Your thyroid affects your ability to absorb nutrients and leads to deficiencies. 
• And lastly, and probably most importantly, these imbalances and problems are NOT solved when you take thyroid medication or even with natural therapies.

Some of the problems which were originally caused by your thyroid may require treatment that is separate from thyroid medication. 

Consider this example:

If you have Vitamin B12 deficiency from hypothyroidism, treating your thyroid appropriately is not enough to fix your B12 problem. 

You will need B12 to fix that problem. 

With this in mind, let’s talk about which lab tests you should get. 

17 Lab tests you Should Get:

#1. Serum Magnesium or RBC Magnesium

It doesn’t matter which type of magnesium you are checking here just make sure that you check it. 

You will see a recurring theme here as it relates to magnesium, Vitamin B12, and folate in that these tests are not super accurate. 

But even though they are not 100% accurate, you should still be ordering them. 

Why?

Because they are accurate when they assess for overt deficiency (meaning your test is obviously too low) but they lose value in the middle to high range. 

In terms of magnesium testing, it’s a good idea to check it because of how your thyroid impacts magnesium metabolism. 

Disordered thyroid tests can lead to urinary changes in the excretion of magnesium and lead to deficiencies. 

RBC magnesium is said to be slightly more accurate than serum magnesium but, in my opinion, it doesn’t matter which one you get because you can still have a normal level and still need magnesium. 

#2. Vitamin B12

Vitamin B12 is another really important nutrient deficiency that is both underdiagnosed and underappreciated. 

B12 deficiency has been seen in anywhere from as much as 30 to 50% of hypothyroid patients (1)!

What’s more concerning is that serum B12 testing is not always accurate (in fact, most of the time it isn’t). 

But, as I said before, you still want to test for it because you will catch very low levels which may necessitate B12 shots. 

B12 deficiency can also lead to hypothyroid-like symptoms such as fatigue and brain fog and replacing thyroid hormone does not replace B12 levels (you need a supplement for that). 

For these reasons, I almost always recommend hypothyroid patients use a B complex (with methylcobalamin) to ensure that they are replacing these B12 levels. 

Methylcobalamin is safe for those with MTHFR defects which affect up to 40% of the population. 

#3. Folate

Folate suffers from the same issues that B12 does but it’s still worth checking (at least once). 

I will occasionally find very low folate levels in addition to B12 levels which can indicate either an MTHFR defect (2) or that the person with both deficiencies is probably also suffering from many other deficiencies. 

Make sure you grab folate with B12 and magnesium. 

#4. Vitamin D3

Vitamin D3 differs from the other nutrients in that the value you get here is actually useful. 

Vitamin D is almost incredibly important when it comes to thyroid function because it influences both your thyroid and your immune status. 

Vitamin D deficiency is associated with an increased risk of depression, fatigue, GI issues, and even autoimmune disease (3). 

Many of these symptoms overlap with those of hypothyroidism (much like the other nutrient deficiencies). 

I consider Vitamin D3 supplementation to be necessary for most thyroid patients simply because of how important it is in overall health and how frequently patients are deficient in it. 

Check your Vitamin D3 level and supplement if you are low. 

My recommended supplement can be found here if you want isolated highly absorbable D3 or you can add it as part of a thyroid multivitamin as well (to get all of the other nutrients). 

#5. Serum Fasting Leptin

Fasting serum leptin is incredibly important to test if you have thyroid conditions and if you are overweight or have trouble losing weight. 

Thyroid hormone directly interacts with leptin levels which is why most thyroid patients (who are also obese) suffer from leptin resistance. 

Treating leptin resistance is NECESSARY if you want to lose weight. 

In fact, leptin resistance makes weight loss very difficult or impossible (depending on how severe it is). 

Make sure you check your FASTING leptin level (12 hours is sufficient). 

I like to check insulin, leptin, cholesterol, and cortisol in the fasted state at around 8 am. 

#6. Serum Fasting Insulin, Hgb A1c, and Blood Glucose

These tests are all designed to assess for one thing:

Insulin resistance.

They are all important and give you a little bit of different information. 

High insulin in the fasted state is probably the strongest indicator of insulin resistance but you will also see high Hgb A1cs and high blood glucose as well. 

Don’t be surprised if one or two of these factors are normal while the third is abnormal. 

Remember:

Tests are not perfect, so you need to layer tests on top of each other to ensure that you see the whole picture. 

#7. Serum Estradiol

There are many ways to test for estrogen but I find that starting with your serum estradiol is the easiest way. 

This test is more useful if you are in the pre-menopausal state, meaning you are still having monthly cycles. 

Estradiol in postmenopausal women is not as helpful because it is almost always zero due to how menopause affects estrogen. 

It’s also not as helpful in the perimenopausal state because of how frequently estrogen and progesterone fluctuate in this state. 

Whatever results you see this month, if you are perimenopausal, might change the next month rendering your result less helpful and actionable. 

Checking your estradiol level can help you understand if your estrogen is too high which is known as estrogen dominance. 

Thyroid disorders often directly impact estrogen and progesterone in such a way that often causes an elevation in estrogen and a corresponding decrease in progesterone. 

This gap or difference between estrogen and progesterone is a problem that many women suffer from. 

#8. Serum Progesterone

Hypothyroidism states directly impact progesterone which is why hypothyroidism is associated with infertility!

You can check your serum progesterone level (ideally sometime in the mid-luteal phase which is around day 19-21 of the typical cycle). 

You should ALWAYS check progesterone with estradiol (or estrogen in general) so you can understand how they relate to one another. 

Checking one by itself will not give you the information you need. 

As a thyroid patient, be sure to watch out for low progesterone levels which are what most of you will probably suffer from. 

Low progesterone causes very specific symptoms and can be treated with over-the-counter supplements and potentially the use of progesterone creams. 

#9. Free and Total Testosterone

Testosterone levels tend to be another casualty of thyroid disorders. 

Many women with hypothyroidism, especially if they have Hashimoto’s will find that their testosterone levels are also low. 

You can check this by looking at both free and total testosterone levels in the serum. 

The test is easy to order and easy to interpret (you just want your tests to be optimal). 

Symptoms of low testosterone in women usually include things like the inability to gain muscle mass, the inability to lose weight, irritability, and decreased libido. 

Low testosterone states also predispose you to develop autoimmune diseases such as Hashimoto’s and can be used as a therapy to treat Hashimoto’s if you know what you are doing. 

Treating testosterone should start with treating your thyroid but you can also use testosterone creams and gels if necessary as well. 

#10. Sex Hormone-Binding Globulin (SHBG for short) 

Sex hormone-binding globulin is another tool that can actually give you important insight as to how well your thyroid medication (or thyroid in general) is functioning. 

SHBG is secreted by the liver and only in response to two hormones:

Estrogen and thyroid hormone. 

So low SHBG in the serum is caused by either liver problems (unlikely), low estrogen (not likely because most women have estrogen dominance), or low thyroid (very likely if you are a thyroid patient!). 

It’s not a perfect test, but it does allow you to get valuable information especially if you are using thyroid medication. 

If you are, you should see your SHBG rise as you take your medication. 

If you are not then this is a sign you are either not converting your medication appropriately (T4 to T3 conversion) or that your medication is not being absorbed (due to gut issues). 

Don’t neglect this test!

#11. Serum Cortisol (8 am)

There are many ways to test your cortisol but I always start with serum cortisol first. 

Why?

It’s cheap, covered by insurance, and doesn’t require any fancy techniques to acquire it. 

All you need to do is make sure you get your blood drawn at 8 am. 

If you get it drawn any later or earlier then your result will not be very accurate. 

Cortisol is often a casualty in hypothyroid patients (4), especially those who suffer from stress-related issues, and your serum cortisol may reflect that. 

The only downside to serum cortisol is that it isn’t 100% accurate or a measure of cortisol in other tissues in your body. 

But, it’s good enough to start with and can give you information if your cortisol is either high or low. 

Please note, though, that normal serum cortisol levels do NOT mean that your adrenals are fine. 

This is why so many people opt to use tests such as salivary cortisol and urinary cortisol. 

You can treat high and low cortisol using adrenal adaptogens such as this one (which can improve your energy levels and stress resilience). 

#12. Iron Studies (ferritin, serum iron, TIBC, % saturation)

There exists a strong connection between your iron levels and how well your thyroid can function. 

This connection is so strong that I’ve spent entire blog posts on the subject. 

I don’t want to re-hash that information but you should be aware that low iron levels impair your thyroid’s ability to function properly. 

In addition, hypothyroidism makes it more likely for you to develop low iron. 

So one can trigger the other in a vicious cycle. 

You can test for iron deficiency by ordering serum TIBC, serum iron, % saturation, and ferritin levels. 

Pay very close attention to your ferritin because ferritin is also required for hair growth as well as thyroid function. 

#13. Cholesterol Studies (HDL, LDL, and total cholesterol)

The cholesterol panel I am talking about here is really just the basic cholesterol panel (not the fancy heart tests from the Cleveland clinic heart lab). 

You really only need the advanced heart/cholesterol tests if you are really worried about cardiovascular disease such as a heart attack. 

And you can always order those tests later (once you get these basic tests firsts). 

The reason we are interested in these tests is that your total cholesterol can be used as a sensitive marker for early thyroid disease (5). 

I’ve seen a number of otherwise normal and healthy patients who have high total cholesterol (along with hypothyroid symptoms) that can be missed by looking at standard thyroid lab tests. 

The link between high cholesterol and hypothyroid states is not controversial (the treatment is another story, but the connection is not). 

Be sure to monitor your total cholesterol as you treat your thyroid. 

#14. Comprehensive Metabolic Panel

The comprehensive metabolic panel, also known as the CMP for short is a set of tests that includes electrolytes and liver/kidney function. 

Just be sure to get this because it contains blood glucose and other important electrolytes such as potassium and sodium. 

#15. Liver/Kidney Function (Creatinine and AST/ALT)

The CMP will also contain information on your kidney and liver function as well. 

We are really interested in the AST and ALT here which give you information about your liver. 

High AST and ALT levels are often associated with a condition known as fatty liver disease which is a sign of insulin resistance. 

If your ALT and AST are elevated then this is a bad state for your thyroid because much of your T4 is converted into T3 in your liver. 

Any inflammation or damage to the liver may impair this process and make your thyroid function worse. 

#16. Inflammatory Markers (ESR, CRP, and Ferritin)

These inflammatory markers help you understand if there is systemic or generalized inflammation in your body. 

They are easy to test for and easy to order. 

The ones you want to look at include ESR (which stands for erythrocyte sedimentation rate), CRP (which stands for C reactive protein), and ferritin (which is an iron study but can double as an inflammatory marker as well). 

If inflammation is present then it poses a problem for your thyroid because inflammation negatively impacts T4 to T3 conversion. 

You can treat high levels of inflammation by finding the source or by using supplements such as fish oil or curcumin. 

There are many others, obviously, but those are probably the best for thyroid patients. 

#17. Autoimmune Markers (Thyroid antibodies such as TgAB and TPOab)

By autoimmune markers, I am really referring to those specific to the thyroid. 

I mention this here because even though I consider these tests to be part of a full thyroid lab test, I still see patients with diagnosed hypothyroidism who have never checked their antibodies. 

The test you will want to order (or get your doctor to order) includes thyroid-peroxidase antibodies and thyroglobulin antibodies. 

The presence of these antibodies is a marker for Hashimoto’s thyroiditis and should be taken seriously. 

If present, this changes how you want to approach treating and managing your thyroid. 

You may also need to check for other markers of autoimmune disease in the future including tests for things like MS, Sjogren’s, Rheumatoid arthritis, and so on. 

Getting Insurance to Cover your Tests

One objection I get from a lot of patients is that their doctor says that insurance won’t cover these tests. 

All I have to say here is that this statement is simply not true. 

I’ve personally ordered this combination on patients hundreds (probably up to thousands) of times and I’ve RARELY run into trouble with insurance companies. 

Even when insurance companies do shoot back they just need an extra diagnosis code to get it covered in full. 

So don’t let your doctor say that it won’t be covered. This is typically code word for “they don’t want to order the tests”. 

Before you get them drawn, however, be sure to communicate with your insurance company to make sure they will cover them!

If these tests are not covered then you may be looking at a bill of over a thousand dollars. 

I’ve found that simply adding the diagnosis code of hypothyroidism and Vitamin D deficiency is enough for 99% of people. 

Final Thoughts

Remember:

These tests should always be ordered in conjunction with your thyroid lab tests! 

These do not replace your thyroid lab tests but should be used in conjunction with them. 

Also, you don’t need to get this work-up every time you get your labs drawn. 

But if you’ve never had this type of work-up in the past, or if you aren’t sure what is going on with your body, then it’s a great place to start. 

Now I want to hear from you:

Have you had a complete work-up in the past?

If so, what things did you find?

If not, are you going to get it done?

If you have any other lab tests that you’ve found to be helpful in your journey please share them below as well!