10 factors that affect your thyroid test results (2023)

FAQs

10 factors that affect your thyroid test results? ›

The thyroid gland needs the mineral iodine to make thyroid hormones. Iodine is found mainly in seafood, seaweed, plants grown in iodine-rich soil and iodized salt. Too little iodine can lead to hypothyroidism. Too much iodine can make hypothyroidism worse in people who already have the condition.

The thyroid gland needs the mineral iodine to make thyroid hormones. Iodine is found mainly in seafood, seaweed, plants grown in iodine-rich soil and iodized salt. Too little iodine can lead to hypothyroidism. Too much iodine can make hypothyroidism worse in people who already have the condition.

This supports the role of TSH, in the absence of hypothalamic/pituitary disease, as the most sensitive marker of thyroid function.

The thyroid “takes up” iodine from the blood to make thyroid hormones, which is why this is called an uptake test. Your health care professional may ask you to avoid foods high in iodine, such as kelp, or medicines containing iodine for a week before the test.

Scientific studies that assessed the effects of caffeine consumption on TSH (a hormone that affects thyroid function) concentrations, observed reduced TSH concentrations as a result of consuming an amount of caffeine equivalent to three cups of coffee.

Smoking mainly led to a decrease in TSH levels and an increase in triiodothyronine (T3) and thyroxine (T4) levels, while BMI levels were positively correlated with TSH and free T3 levels. Excess iodine led to an increase in TSH levels and a decrease in thyroid hormone levels.

Medication Use and Thyroid Test Results. Certain medications can cause thyroid dysfunction. These drugs can interfere with your thyroid hormone levels or with their action. This may alter TSH because your body may try to compensate for the high or low thyroid hormones.

Dehydration can cause an increase in cortisol production stressing the adrenals and further initiate production of TSH, which again has a negative impact on thyroid.

Available studies confirmed a link between thyroid function and inflammatory markers, such as ferritin, fibrinogen, erythrocyte sedimentation rate, interleukin-8, interleukin-15, or LYMPH (14, 20, 24).

What are early warning signs of thyroid problems? ›

TSH normal values are 0.5 to 5.0 mIU/L. Pregnancy, a history of thyroid cancer, history of pituitary gland disease, and older age are some situations when TSH is optimally maintained in a different range as guided by an endocrinologist.

The ATA has recommended that patients stop taking biotin for at least 2 days before thyroid testing to avoid the risk of having a misleading test.

Normal Results

It is best to have the test early in the morning. Experts do not fully agree on what the upper number should be when diagnosing thyroid disorders. Some labs will use a higher normal range limit for older people (even as high as 7 µU/mL). Normal value ranges may vary slightly among different laboratories.

So again, with this medication type, I recommend getting your thyroid function tests done first thing in the morning before taking your medications, bringing your medications with you, and taking them right after you complete your thyroid tests, to ensure that you get the most accurate lab results.

Sleep deviation can alter the function of the human hypothalamic-pituitary-thyroid axis; and is associated with altered levels of TSH, T4, and T3¹⁵. There is also a correlation between poor sleep quality and subclinical hypothyroidism¹⁶.

Sleep loss can also affect the function of the human hypothalamo-pituitary-thyroid axis. In contrast to the effects of sleep deprivation in rodents, acute sleep loss in humans is associated with increased TSH, T4, and T3,^6,7 and human sleep is believed to have an acute inhibitory effect on overnight TSH secretion.

Daily circadian rhythms cause TSH to fluctuate by as much as 0.95 mIU/mL to 2.0 mIU/mL throughout the day. TSH levels are highest in the early morning and decrease late afternoon to mid-evening. TSH levels even fluctuate on average 0.75 mIU/mL on a monthly basis in healthy adults.

TSH tells your thyroid how much thyroid hormone it needs to make. If the thyroid hormone levels in your blood are too low, your pituitary gland makes larger amounts of TSH to tell your thyroid to work harder. If your thyroid hormone levels are too high, the pituitary gland makes little or no TSH.

How often are thyroid tests wrong? ›

Experts have suggested that the standard TSH range could be missing as many as 75% of people with low thyroid. So if your TSH is 2.5 or higher, and you have symptoms of low thyroid, ask your doctor for some additional thyroid tests, like Free T3 and Free T4.

For example, many thyroid supplements contain high amounts of iodine and may contain thyroid hormones. Taking these supplements can lead to dangerous side effects and create thyroid issues in people with healthy thyroid function ( 11 ).

Slightly elevated TSH levels are usually detected by accident during a routine examination. But taken on their own they don't pose any health risk. It's also possible that TSH levels are high only temporarily, for example after intense physical activity.

While heavy metals are abundant in the environment, four specific heavy metals damage the thyroid the most. Those heavy metals are aluminum, cadmium, lead, and mercury.

Therefore, even under the same stress conditions, TSH levels may vary from person to person. In addition, stress exacerbates autoimmune thyroid diseases, such as Graves' disease and Hashimoto's thyroiditis, leading to elevated thyroid hormone and decreased TSH levels [10].

Thyroiditis represents a group of conditions that cause inflammation of your thyroid gland. Hashimoto's thyroiditis is the most common type.

An inflamed thyroid may occur in response to a viral infection (viral thyroiditis) or a bacterial infection (bacterial thyroiditis), after radiation, or in response to certain medications. Your doctor will determine the cause of your thyroiditis and will then treat the condition as needed.

The most obvious symptom of subacute thyroiditis is pain in the neck caused by a swollen and inflamed thyroid gland. Sometimes, the pain can spread (radiate) to the jaw or ears. The thyroid gland may be painful and swollen for weeks or, in rare cases, months.

The lack of thyroid hormones can cause disturbances in your metabolism, including your heart rate and body temperature. Fatigue, sensitivity to the cold, constipation, dry skin, and unexpected weight gain are among the main symptoms.

Cruciferous vegetables – Vegetables such as broccoli, cabbage, kale and Brussels sprouts can inhibit the production of thyroid hormone. This is especially common in those who have an iodine deficiency. Digesting these vegetables can block the ability to absorb iodine, which is needed for normal thyroid function.

What do your hands look like if you have hypothyroidism? ›

A swollen fingertip, curved nail, and thickening skin above a nail are often signs of thyroid disease.

If your TSH level is higher than 10 mIU/L, you should start treatment, because you will very likely develop symptoms of an underactive thyroid, even if you don't have them now.

The best way to control your thyroid is to incorporate Vitamin A in your daily life routine. All you need to do is to consume food products that are high in Vitamin A. The most common Vitamin A rich foods are; yellow and green veggies, carrots, eggs, apricots, spinach, carrots, etc.

If you do not take your thyroid medications consistently or correctly, the therapeutic drug level—meaning the concentration of medication in your body needed for the drug to work—can quickly drop. Without a consistent therapeutic drug level, your thyroid hormone levels can fluctuate, sometimes precipitously.

The presence of human anti-animal antibodies in patient serum may interfere with TSH measurement [45]. If the antibodies block TSH binding to capture or detection antibodies in the assays, negative interference will occur, leading to falsely low TSH levels.

In addition, stress exacerbates autoimmune thyroid diseases, such as Graves' disease and Hashimoto's thyroiditis, leading to elevated thyroid hormone and decreased TSH levels [10].

TSH levels fluctuate over time within a person, in euthyroid individuals as well as in most (un)treated patients with thyroid disorders, ranging from minutes, hours, months, to years. These within-person variations in TSH levels are mainly caused by pulsatile secretion, circadian rhythm, seasons, and ageing.

TSH levels measured in blood samples drawn in the afternoon should be viewed with caution, as they may be falsely low and appear normal. Samples for all thyroid tests should be collected first thing in the morning.

According to the Mayo Clinic, supplements such as calcium, iron, multivitamins containing iron, and antacids containing magnesium or aluminum can potentially have interactions with thyroid medications.

What time of day is TSH lowest? ›

Circulating TSH shows a normal circadian rhythm with a peak between 11 pm and 5 am and a nadir between 5 pm and 8 pm.

Well I'm going to tell you why, in too many cases, the TSH test is unreliable — in which case you could indeed be hypothyroid, but it's going undetected. As a brief reminder, your pituitary pumps out TSH when your thyroid hormones are too low.

Jauch-Chara et al. indicated that an up-regulation of pituitary-thyroid activity, after short-term total sleep deprivation, led to an increase in TSH levels. Kuetting et al. found that sleep deprivation significantly increases cardiac contractility, blood pressure, and stress hormone secretion.

Anxiety Symptoms to Watch For

If you've been diagnosed with hypothyroidism, anxiety symptoms to monitor yourself for include: Insomnia. Feeling “on edge” a lot. Muscle tension.

They also measured their levels of T4 and T3. The researchers found that the thyroids of people with anxiety disorders exhibited signs of inflammation. They also detected thyroid antibodies in these individuals. Even though the participants' thyroid glands were inflamed, they were not significantly malfunctioning.

Daily circadian rhythms cause TSH to fluctuate by as much as 0.95 mIU/mL to 2.0 mIU/mL throughout the day. TSH levels are highest in the early morning and decrease late afternoon to mid-evening. TSH levels even fluctuate on average 0.75 mIU/mL on a monthly basis in healthy adults.

Generally, there's no hypothyroidism diet. Although claims about hypothyroidism diets abound, there's no evidence that eating or avoiding certain foods will improve thyroid function in people with hypothyroidism. However, adequate dietary iodine is essential for normal thyroid function.