Tag: normal hormone levels women

You’ve just received your hormone test results. There are numbers, units, and a column of figures labelled ” hormone reference range” and it’s not immediately obvious what any of it means, or whether you should be worried. You’re not alone. Hormone reference ranges are one of the most misunderstood parts of any blood test result. At Hertility, we interpret your hormone results in clinical context, not just against a number. This guide explains what reference ranges actually are, why they vary, and how to read your results properly. Quick summary What is a hormone reference range? When you receive hormone test results, each value is accompanied by a reference range, a set of numbers that tells you where your result sits relative to a defined population.  The first step in understanding where a reference range comes from is to remember that we expect different things from different groups of people. This can be age-related or gender-related, but can also be lifestyle-related. In actual fact, the ideal ranges are usually pretty broad and rarely take important factors such as ethnicity into account. They are usually defined by the population to which the range will apply (in this case women), but also their age. A large number of individuals from a group who are thought to represent a “normal” population, will be tested for a particular laboratory test. The reference range is then derived mathematically by taking the average value for the group and allowing for natural variation around that value (plus or minus 2 standard deviations from the average). In this way, ranges quoted by labs will represent the values found in 95% of individuals in the chosen ‘reference’ group. In other words, even in a “normal” population, a test result will lie outside the reference range in 5% of cases (1 in 20).  This is precisely why the term “reference range” is preferred over “normal range” in clinical medicine. A result outside the range is not automatically abnormal. A result inside the range is not automatically healthy. The range is a reference point, a tool to aid interpretation, not a binary verdict on your health. Why do hormone reference ranges vary between labs? One of the most confusing aspects of hormone testing is that you can test at two different labs and receive two different results, and both can be correct. This happens for several reasons. Lab environment and equipment. Every laboratory uses precisely calibrated equipment and specific reagents (the chemical substances used to detect hormone levels in a blood sample). Minor differences between labs like temperature, supplier of testing materials, calibration protocols, mean that the same sample can produce slightly different numerical results when analysed in different settings. Neither lab is producing an incorrect result. They are simply measuring with different tools, against different benchmarks. Different reference populations. Each lab establishes its reference range by testing its own reference population. If Lab A and Lab B each test a group of healthy women but recruit from different populations, ages, or regions, their resulting ranges may differ, even if the underlying biology is identical. What this means in practice. If you test at one lab and retest a month later at a different lab, a change in your result may reflect the different reference populations of each lab rather than a genuine change in your hormone levels. This is why, whenever possible, it is best to retest at the same lab  and why any result should always be interpreted against the reference range of the specific lab that analysed your sample, not a generic “normal” value found online. Type of sample: Reference ranges are also different depending on the type of sample used to measure a hormone. Take oestrogen as an example. Oestrogen can be measured in blood, saliva, or urine, but the concentration of oestrogen differs significantly between each of these, and so the reference ranges are different too. This is relevant if you ever compare results from different types of tests. A blood oestrogen result and a urine oestrogen result cannot be directly compared, even if they are measuring the same hormone. The numbers will look different, the reference ranges will be different, and the clinical interpretation will differ accordingly. How hormone reference ranges are categorised by age, sex, and cycle phase Because different groups of people have different hormone levels for entirely normal physiological reasons, reference ranges are not one-size-fits-all. They are adjusted for the characteristics of the population being assessed. By sex Testosterone is a clear example. Men have significantly higher testosterone levels than women, so separate reference ranges exist for each sex. Applying a male testosterone reference range to a female result or vice versa  would make most healthy women appear deficient. By age Many reproductive hormones change significantly across a woman’s lifespan. AMH (anti-Müllerian hormone), which reflects ovarian reserve, naturally declines with age. It would be clinically meaningless to compare a 22-year-old’s AMH to a 42-year-old’s using the same reference range, the 22-year-old would almost always appear to have “better” results simply because of age, not because of any meaningful difference in health status. At Hertility, we use age-stratified reference ranges for AMH and other hormones that change across the reproductive lifespan. This means your result is compared to the expected range for people your age, giving you a more accurate and clinically meaningful interpretation. By cycle phase Cycling hormones like FSH, LH, oestradiol, and progesterone fluctuate significantly throughout the menstrual cycle. Their reference ranges are therefore tied to a specific phase of the cycle. FSH, LH and oestradiol, for example, are typically measured on day 2 or 3 of the menstrual cycle, because the reference ranges for these hormones are calculated on day 3 of a healthy population’s cycle. Testing FSH on day 14 (mid-cycle, around ovulation) and comparing it against a day 3 reference range would produce a meaningless result because LH surges dramatically at ovulation, and FSH also rises. The timing of the test and the timing of the reference […]