Iodine test at home – iodine in morning urine (urine test)

The body excretes most of the iodine it takes in via the kidneys. The iodine concentration in urine therefore shows how much iodine was taken in over the last few days. A low value indicates low iodine intake during that period.

Important for interpretation: iodine excretion varies greatly from day to day. In a study of healthy women, about ten urine samples were needed to estimate an individual's iodine status with 20% precision (PubMed 21918061). A single value is therefore a snapshot of recent intake, not a reliable statement about iodine deficiency.

A high value results from high iodine intake in the days before the sample, for example from iodine supplements, seaweed, iodine-containing medication or iodine-containing contrast agents used in X-ray and CT scans. Most people tolerate higher intake well. In certain groups – people with thyroid disease, older people, unborn and newborn babies – too much iodine can, however, trigger an under- or overactive thyroid (PubMed 24342882).

The report gives two values. The main value states iodine relative to creatinine (µg/g creatinine). Creatinine is excreted fairly evenly; the ratio therefore compensates for whether urine is diluted or concentrated by drinking a lot or a little. The second value is the absolute iodine concentration in µg/l.

For the main value, the sample report shows the laboratory's classification from "optimal supply" to "severe deficiency". This classification comes from the laboratory; because of day-to-day variation, it is only of limited significance for an individual.

Iodine is a trace element that the body cannot make itself. The thyroid needs it to produce its hormones thyroxine (T4) and triiodothyronine (T3). Important sources are iodised table salt, dairy products, bread made with iodised salt and sea fish (PubMed 24342882).

Iodine deficiency early in life impairs growth and cognitive development; in adults, iodine status is an important determinant of thyroid disorders (PubMed 25591468).

Until the early 1990s, there was mild to moderate iodine deficiency in large parts of Germany; iodised table salt improved supply. More recent data from studies of children suggest that iodine supply has worsened again (PubMed 35043251).

How well a population is supplied is determined from the median of many urine samples – urinary iodine is well suited for this. For an individual, by contrast, there is no established single marker (PubMed 21918061).

Since the body excretes iodine mainly in urine, urinary iodine measurement is the usual method for assessing iodine intake (PubMed 21918061). Measuring iodine in blood is not common for this purpose.

The urine test does not show how the thyroid is working. For that, TSH and, if necessary, thyroid hormones are measured in blood (PubMed 28336049).

The test shows iodine excretion at the time of sampling and thus intake over the past few days. Because this varies greatly, a single value says little about an individual's long-term supply (PubMed 21918061). Meals, supplements and iodine-containing contrast agents before the sample influence the result.

The test can be a basis for a conversation about iodine intake; it can neither detect nor rule out thyroid disease.

Research associates iodine deficiency with the following consequences, with varying strength of evidence:

• Enlarged thyroid (goitre), which can be noticed as a swelling in the neck: well documented in severe iodine deficiency (PubMed 25591468).
• Underactive thyroid with fatigue, lethargy, cold intolerance, weight gain, constipation, dry skin and a changed voice: well documented in severe deficiency (PubMed 25591468, PubMed 28336049).
• Thyroid nodules and overactivity: with mild to moderate deficiency, the thyroid works harder over the long term; nodular changes and overactivity then occur more often in the population – well documented (PubMed 25591468).
• Growth and cognitive development in children: iodine deficiency early in life impairs both – well documented (PubMed 25591468).

Mild iodine deficiency often causes no noticeable complaints.

These are associations from studies and textbook knowledge, not causes in an individual person. A urine test cannot explain complaints and does not provide a diagnosis. Persistent complaints should first be assessed by a doctor.

With a swelling or lump in the neck, difficulty swallowing or breathing, persistent hoarseness, a racing heart, tremor, unintended weight loss or clear signs of an underactive thyroid, the first step is a doctor's practice, not a self-test. There, TSH and, if needed, further values and an ultrasound are arranged.

With known thyroid disease, during pregnancy and breastfeeding and before taking iodine supplements, the question of iodine belongs in medical care, because too much iodine can be harmful in these situations.

This page does not recommend supplements, diets or therapies. Whether a value means anything at all and which steps make sense depends on your overall situation: complaints, previous illnesses, medication and diet. Too much iodine can trigger thyroid dysfunction in susceptible people (PubMed 24342882).

What makes sense for you belongs in a conversation with the ORY expert team or with your doctor or naturopath, for example from the ORY expert network. The results consultation is included in the price.

Use the first morning urine directly after getting up. Collect the midstream urine – not the first and last part – and fill it into the urine monovette with the collection tip attached. Put the monovette into the transport tube, fill in the request form completely, sign it and note the date of collection.

No cooling is needed. Send the sample from Monday to Thursday, not on Fridays or before public holidays. Iodine supplements, seaweed or an iodine-containing contrast agent in the days before the sample influence the value; mention them in the results consultation.

Analysis usually takes 7–21 days from the arrival of the sample at the laboratory. As soon as your report is ready, we let you know. A results consultation with the ORY expert team is included in the price.

The iodine test costs €78 including VAT, shipping, return postage and results consultation.

Statutory health insurance in Germany generally does not cover urinary iodine tests you order yourself. With private insurance, reimbursement may be possible; how it works is described under "Reimbursement by private insurance".

The iodine test (€78) measures iodine excretion in morning urine. The thyroid value TSH is included in the OM Vital blood test (€205) together with blood lipids, liver and kidney values and vitamins. Selenium, which the thyroid also needs, is measured by the whole blood mineral analysis (€75).

Which scope makes sense for you can be clarified in the free initial consultation.