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Is Bloodwork Enough to Assess Thyroid Health?

Testing Thyroid Health

The thyroid is a complex system involving many factors spanning multiple regions of the body. Therefore, thoroughly testing the health, function, and activity of the thyroid requires investigation of the various factors involved. Unfortunately, the current standard for thyroid testing relies on few elements and does not provide an accurate assessment of individual thyroid function.

The Current State of Thyroid Testing

Currently, thyroid patients are assessed using serum levels (blood concentration) of various hormones. A thyroid blood test may include thyroid hormones such as TSH, T4, T3, and Reverse T3. However, even though these tests are useful in estimating thyroid function, they do not provide a full picture.

Sadly, most physicians rely solely on serum levels of TSH to assess thyroid function. On its own, the TSH test is insufficient and woefully inaccurate. Furthermore, thyroid blood tests may not detect hypothyroidism even if a patient is symptomatic. Because so many practitioners only use TSH as the metric for thyroid wellness, many patients remain undiagnosed and unwittingly suffer from a thyroid disorder.

The Problem with Blood Tests

Part of the reason blood testing is not an effective way of gauging thyroid function is because it does not assess tissue levels of thyroid hormone. It is common for patients who are dieting, depressed, or experiencing physiological stress, and inflammation to have reduced tissue levels of thyroid hormones but maintain “normal” serum levels of TSH. Because TSH only reflects hormone activity in the pituitary, a patient may have significantly reduced tissue levels of active thyroid hormone T3 elsewhere but still maintain nominal TSH levels.

Another aspect of thyroid health that is not recognized through blood testing are issues pertaining to hormone conversion. If T4 is not converted into T3 at the appropriate rate, levels of T4 will remain within a normal range while concentrations of T3 continue to decrease or remain deficient. Furthermore, imbalanced conversion of T4 into Reverse T3 may result in significantly reduced prevalence and functionality of T3 even though levels of T4 remain consistent. Most blood tests do not recognize conversion issues, which often results in physicians overlooking existing thyroid dysfunction in their patients.

The Importance of Accurate Testing

Medical professionals estimate that up to 80% of the population has some degree of thyroid dysfunction. Sadly, many of these cases are overlooked due to poor testing practices. More than TSH and thyroid blood tests must be administered to effectively assess the wellness of the thyroid. The following testing methods provide important information allowing for better assessment of thyroid function.

Basal Metabolic Rate

Testing the metabolic rate can be useful in both diagnosing and monitoring thyroid conditions. It also provides a more accurate image of thyroid function than typical blood tests. Because the thyroid is integral to metabolic activity and regulation, measuring individual metabolic function can provide critical insight into thyroid activity. If a patient has a notably reduced basal metabolic rate (BMR), it is likely that they are suffering from hypothyroidism. Alternatively, an elevated BMR is indicative of hyperthyroidism.

Determining BMR can be done by calculating the amount of oxygen the body consumes. There is a direct correlation between the amount of oxygen consumed and the number of calories the body burns while at rest. After calculating this number, it is possible to assess the body’s BMR. This method is known as indirect calorimetry and can be used to calculate metabolic rate and by extension thyroid activity. Ideally, a patient’s BMR falls within an appropriate and healthy range. If it does not, a thyroid condition may be present.

Iodine Levels

Iodine is an essential building block of thyroid hormones and is used in many other systems including the liver and adrenals. An iodine deficiency may result in hypothyroidism and thyroid inflammation while increased levels frequently cause hyperthyroidism. Because of its close relationship with thyroid function, iodine testing can provide an accurate appraisal of thyroid activity.

Fortunately, iodine testing is incredibly easy and doesn’t even require fasting or the cessation of medication. A simple urine test can provide an accurate assessment of current iodine levels. This easily conducted test provides insight into iodine prevalence, and by extension thyroid hormone production, which is an important piece of information that is overlooked by standard thyroid blood tests.


One of the issues of thyroid blood testing is that it cannot assess T3 levels within cells. However, with Thyroflex testing, cellular T3 levels can be gauged. The speed at which a nerve responds or reacts to stimulation is determined in part by the concentration of active thyroid hormone in cells and tissues. T3 is required for cellular activity and as levels decrease so does cellular energy and nerve reactivity. Reduced reactivity, or nerve conduction, indicates slowed cellular function and reduced thyroid hormone levels.

By measuring the transmission of nerve impulses moving through muscle cells and nerves we can assess thyroid activity. Essentially, the Thyroflex measures the amount of time it takes for a nerve impulse to trigger a physical reaction. More specifically, the Thyroflex test calculates conduction velocity through a tendon reflex to gauge thyroid activity. Most are familiar with the small rubber mallet being tapped on the knee to assess reaction time. The Thyroflex test works in a similar fashion but technological assistance now allows for more accurate measurement of this response which can be used to calculate thyroid activity.

Better Testing for Better Treatment

Many people with thyroid conditions are unaware of their condition. A significant contributor to this issue is inadequate testing practices. Standard blood testing used to assess thyroid function provides relevant information but not enough to provide a true diagnosis. To attain an accurate picture of individual thyroid function, additional testing such as the Thyroflex, basal metabolic rate, and iodine levels should be utilized. Using such tests provides a more precise diagnosis which facilitates more accurate and effective treatment.


1. Other (Non-Blood) Thyroid Tests You May Not Know About. Holtorf Medical Group.

2. Thyroflex Test: When you are being treated for hypothyroidism but still feel awful. Hypothyroid Mom.

3. Thyroflex Test. Thyroflex.

4. Measuring Metabolic Rate for Your Thyroid. Thyroid Nation.

5. Urine Iodine Test. Life Extension.

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