Spreadsheet for Calculating Free T & E2

[Simon7]

There's been a lot discussion recently in Excelmale on wanting to test for Free E2 and the relatively high cost of this test. There are online calculators which calculate an estimate of Free T based on Total T, SHBG and Albumin. However there doesn't appear to be an online calculator for estimating Free E2.

I researched the topic and found an article from 2010 by Norman Mazer, Ph.D, who created an Excel spreadsheet for calculating Free T, Free E2, Free DHT and others. The first tab in the spreadsheet is titled "user interface" and you input there the values of Total T, Total E2, Albumin and SHBG and the spreadsheet calculates the Free values.

I modified the spreadsheet slightly to make it more user friendly - changed the titles, highlighted the fields to be inputed in Blue and the results in green, and added ability to input data in nmol/L and pmol/L units and to auto convert these units. You can download the modified spreadsheet .

Enjoy!

[Moderator's note: The original links are dead, so I have attached a copy of the spreadsheet.]

 

[rafapark]

There's been a lot discussion recently in Excelmale on wanting to test for Free E2 and the relatively high cost of this test. There are online calculators which calculate an estimate of Free T based on Total T, SHBG and Albumin. However there doesn't appear to be an online calculator for estimating Free E2.

I researched the topic and found an article from 2010 by Norman Mazer, Ph.D, who created an Excel spreadsheet for calculating Free T, Free E2, Free DHT and others. The first tab in the spreadsheet is titled "user interface" and you input there the values of Total T, Total E2, Albumin and SHBG and the spreadsheet calculates the Free values.

I modified the spreadsheet slightly to make it more user friendly - changed the titles, highlighted the fields to be inputed in Blue and the results in green, and added ability to input data in nmol/L and pmol/L units and to auto convert these units. You can download the modified spreadsheet .

Enjoy!

I can download it but it does not open for some reason.

 

[BenM]

Confirmed, it won't open for me either - Excel says the file is corrupt and cannot be opened.

 

[madman]

There's been a lot discussion recently in Excelmale on wanting to test for Free E2 and the relatively high cost of this test. There are online calculators which calculate an estimate of Free T based on Total T, SHBG and Albumin. However there doesn't appear to be an online calculator for estimating Free E2.

I researched the topic and found an article from 2010 by Norman Mazer, Ph.D, who created an Excel spreadsheet for calculating Free T, Free E2, Free DHT and others. The first tab in the spreadsheet is titled "user interface" and you input there the values of Total T, Total E2, Albumin and SHBG and the spreadsheet calculates the Free values.

I modified the spreadsheet slightly to make it more user friendly - changed the titles, highlighted the fields to be inputed in Blue and the results in green, and added ability to input data in nmol/L and pmol/L units and to auto convert these units. You can download the modified spreadsheet .

Enjoy!

ABSTRACT
SHBG is a plasma protein that participates in the regulation of free estradiol and free testosterone in plasma. We discuss the concept of the nature of a free estradiol and how best to ascertain its value. It can be measured or calculated; the ways in which this can be done are explored along with the advantages and disadvantages of each.




1. Introduction

The theme of this special issue is estradiol (E2); the purpose of this communication is to set out the role of sex hormone-binding globulin (SHBG) in relationship to free estradiol in human plasma. However, we would be remiss if we omitted mention of SHBG’s multiple other functionalities. It participates in signal transduction at the plasma membrane where it has a specific binding site [1]; it is a predictor/marker of a number of important disease states [2]; and it is synthesized in a number of tissues, that are unrelated to its presence in plasma, and, in prostate, enhances the action of dihydrotestosterone [3] Thus, although this communication will deal only with SHBG’s function relative to the binding of E2, we should recall that it is a multi-functional protein whose biology is far from clearly understood.




1.1. SHBG general properties
The first descriptions of SHBG established that it was a plasma glycoprotein that circulates as a homodimer that binds a variety of sex steroids, most importantly dihydrotestosterone, testosterone (T) and estradiol. It subsequently became clear that the homodimer binds two molecules of ligand [4], and that the source of plasma SHBG is the liver [5], which synthesizes and secretes it. Its concentration in plasma is known to be increased by thyroid hormone, estrogenic hormones, and cirrhosis whereas its concentration is decreased by obesity, androgens, prolactin, puberty, progestins, insulin and IGF-1.


1.2. Free estradiol
E2 is presumed to exist in two physical states in human plasma – that which is bound to proteins and that which is unbound (free). The two proteins that bind E2 are SHBG and albumin. We should be aware that the concept of free estradiol concentration is a theoretical construct and that free or bound hormone is not measured directly in vivo, but rather examined in vitro by a number of techniques which attempt not to disturb the presumed equilibrium which exists in vivo. The theoretical construct arises from the Law of Mass Action which describes the distribution of two or more interacting molecular entities based on their molar concentration and the quantitative strength of the interaction, e.g. the association constant (Ka). The original work on Mass Action was done on chemical kinetics in simplified systems with reactants in a relatively dilute, pH-buffered, aqueous solution. In more complex environments, where bound particles may be prevented from dissociation by their environment, the model of Mass Action may not always describe the behavior of the reaction kinetics accurately. This caveat may bear on some of the inconsistencies between measured and calculated free estradiol discussed below. Fig. 1 sets out, in a formal manner, how one predicts the concentration of free estradiol if the concentration of SHBG, albumin, total estradiol and the appropriate Ka’s are known. Note that this is a cubic equation which may not be familiar, as the two most common expositions of the Law of Mass Action, as applied to this circumstance, result in quadratic equations after a simplifying assumption [7,8]. The simplifications are justified and if all the same numbers are entered into the equations, they all yield the same result. Several intuitive and useful messages are inherent in these equations:


-Increases in SHBG or Ka decrease free E2.

-Increments in an existing excess of total E2 over SHBG all go to free E2.

-When total E2 is small compared to SHBG, the fraction bound depends only on the Ka and SHBG concentration.

- When SHBG and E2 are more or less equal the fraction of E2 bound depends on [total E2], [SHBG], Ka and on [total E2]/ [SHBG].







2. Free E2: calculate or measure?

2.1. Calculate
Substantially more effort has gone into examining the vagaries of free T than free E2. Although there are distinct differences in estimating free T and free E2, the general approaches are the same and, as appropriate, we will cite papers dealing with the approach to calculating/measuring free T. To calculate free estradiol one must first have an accurate measure of total estradiol, SHBG, albumin, and the appropriate Ka’s. The difficulties with, and problems of, assaying estradiol constitute a large part of this special issue and I would simply emphasize that without a proper assay for total estradiol, there can be no accurate determination of free estradiol. SHBG can be measured, either by its ligand binding capacity, by immunoassay or, more recently by mass spectrometry [9]. Commercial methods are available for its immunoassay. At least some of those assays have been standardized against the binding capacity of a standard SHBG preparation obtained from the WHO. There are however problems with the standard; its binding capacity is lower than the previous standards, and its Ka for the SHBG steroid interaction is also lower [10]. Further, one need be sure that the standard’s binding activity is equal to its immunologic activity as the two activities must be proven to be identical and are differentially sensitive to denaturation. Estimation of the proper association constants for E2-SHBG and E2-albumin are problematic (Table 1). As can be seen, there is a >3-fold difference in the highest vs. the lowest Ka for estradiol-SHBG and an almost 2-fold difference in the highest vs. the lowest Ka for estradiol–albumin. Thus, depending on the choice of Ka, widely discrepant values would be calculated. Finally, it is possible for a variety of other steroids to compete for binding with E2. This would raise the concentration of free estradiol, but is not ordinarily taken into account in calculated values. For the most part, this does not appear to be a problem in non-pregnant women (in whom competing steroids do not circulate in sufficiently high concentrations to increase free estradiol) but can yield incorrect results in the presence of unsuspected competitors or in known situations, such as male plasma, where the concentration of T far exceeds that of estradiol and displaces it from SHBG binding sites. If competitors are present and measured, the overall binding equations can be altered and appropriate corrections can be made [11]. Despite all these caveats, calculation is the prevalent way that free E2 is estimated. For those agreeing on the various measurements, and using the same Ka’s, the results can be comparable, thus giving the false impression of ‘‘accuracy by the majority.’’ Finally, it has been suggested that the binding of ligands to SHBG is allosteric and that the two binding sites on the homodimer do not have the same Ka. Occupancy of one of the sites on the homodimer is posited to alter the Ka of the other. Modeling based on this concept is said to result in calculated values in better agreement with careful measurements of free estradiol than previous models [12].





2.2. Measure
As stated above, free E2 in plasma is a theoretical construct that follows from the Law of Mass Action which was formulated by chemists in the late 1800’s and ‘‘explains and predicts behaviours [sic] of solutes in dynamic equilibrium.’’ Acceptance of the Law of Mass Action does not necessarily imply that all the components of an equilibrium mixture can be accurately measured or, indeed, how it is to be done. Whatever method is used ideally should not: disturb the equilibrium that exists in vivo; change the environment that exists in vivo (ionic strength pH, etc); and be accomplished at the same temperature that exists in vivo. The two methods that best approximate these criteria are equilibrium dialysis and centrifugal ultrafiltration (see Table 2).



2.2.3. Choose a method
The choice is guided by both convenience/ease and the desire to obtain the answer most likely to coincide with the true value of free E2. Whichever method one chooses, E2 must be accurately and reproducibly measured; this is required whether one calculates or measures. Once having conceded the ability to measure E2, then the calculation offers the advantages of simplicity and economy. SHBG and albumin are easily measured and the calculation is automated. On the negative side: there is disagreement about the proper Ka’s and SHBG is not properly standardized/harmonized. In spite of these potential hazards, a number of communications have claimed excellent agreement between calculated and measured values for free testosterone [13,16,20] and free estradiol [13]; however, a number of publications find disagreement between measured and calculated values [21–23]. In addition the calculation of free E2 has been compared to measured values, and found to be satisfactory, in only a small sample of postmenopausal patients [13]; the authors caution against using the calculated value in other populations. Moreover, it should be recalled that E2 is bound to SHBG 2–3-fold less tightly to SHBG than is testosterone, rendering the assumption of a fixed value for albumin unacceptable until the appropriate calculations and experiments are at hand. This is still an unsettled issue and no irreversible recommendations as to the best way to proceed can be issued at this time.

 

[Vince Carter]

Given it says you need "Total Estradiol" to make the calculation I'll just keep on testing Free Estradiol. If I'm adding adding a test I wouldn't have otherwise just to make a calculation from a test that I could have just taken in the first place...makes no sense at all unless "Total Estradiol" is far cheaper test which there's no dollar value attached there.

I appreciate the effort you make here but this makes no sense to substitute one test for another until the retail dollar value is known for the guy.

 

[Simon7]

Rafapark & Benm, thanks for your feedback. I replaced the excel file and updated it to .xlsx and it seems fine now. Here's the download link again. Let me know how you like it.

Vince, the benefit of the above spreadsheet is to have the Total T and Total E2 adjusted with SHBG and albumin to calculate Free T and Free E2, at no extra cost. I don't have Free E2 test where I live and others here commented that the Free E2 test is quite expensive.

It would be interesting for folks who have tested their Free E2 to compare and post here the results of Free E2 and calculated E2 by the above spreadsheet, so we can see how accurate the calculated estimate is.

 

[Vince Carter]

I get it, though here, we don't test Total Estradiol so it get's kind of to being a moot point for US guys but clear and valid point for you that don't have the access to these tests.

 

[Simon7]

People post here E2 results all the time, usually sensitive E2 essays . They don't refer to it as "total E2" , but that's what they are.

 

[Gman86]

ABSTRACT
SHBG is a plasma protein that participates in the regulation of free estradiol and free testosterone in plasma. We discuss the concept of the nature of a free estradiol and how best to ascertain its value. It can be measured or calculated; the ways in which this can be done are explored along with the advantages and disadvantages of each.




1. Introduction

The theme of this special issue is estradiol (E2); the purpose of this communication is to set out the role of sex hormone-binding globulin (SHBG) in relationship to free estradiol in human plasma. However, we would be remiss if we omitted mention of SHBG’s multiple other functionalities. It participates in signal transduction at the plasma membrane where it has a specific binding site [1]; it is a predictor/marker of a number of important disease states [2]; and it is synthesized in a number of tissues, that are unrelated to its presence in plasma, and, in prostate, enhances the action of dihydrotestosterone [3] Thus, although this communication will deal only with SHBG’s function relative to the binding of E2, we should recall that it is a multi-functional protein whose biology is far from clearly understood.




1.1. SHBG general properties
The first descriptions of SHBG established that it was a plasma glycoprotein that circulates as a homodimer that binds a variety of sex steroids, most importantly dihydrotestosterone, testosterone (T) and estradiol. It subsequently became clear that the homodimer binds two molecules of ligand [4], and that the source of plasma SHBG is the liver [5], which synthesizes and secretes it. Its concentration in plasma is known to be increased by thyroid hormone, estrogenic hormones, and cirrhosis whereas its concentration is decreased by obesity, androgens, prolactin, puberty, progestins, insulin and IGF-1.


1.2. Free estradiol
E2 is presumed to exist in two physical states in human plasma – that which is bound to proteins and that which is unbound (free). The two proteins that bind E2 are SHBG and albumin. We should be aware that the concept of free estradiol concentration is a theoretical construct and that free or bound hormone is not measured directly in vivo, but rather examined in vitro by a number of techniques which attempt not to disturb the presumed equilibrium which exists in vivo. The theoretical construct arises from the Law of Mass Action which describes the distribution of two or more interacting molecular entities based on their molar concentration and the quantitative strength of the interaction, e.g. the association constant (Ka). The original work on Mass Action was done on chemical kinetics in simplified systems with reactants in a relatively dilute, pH-buffered, aqueous solution. In more complex environments, where bound particles may be prevented from dissociation by their environment, the model of Mass Action may not always describe the behavior of the reaction kinetics accurately. This caveat may bear on some of the inconsistencies between measured and calculated free estradiol discussed below. Fig. 1 sets out, in a formal manner, how one predicts the concentration of free estradiol if the concentration of SHBG, albumin, total estradiol and the appropriate Ka’s are known. Note that this is a cubic equation which may not be familiar, as the two most common expositions of the Law of Mass Action, as applied to this circumstance, result in quadratic equations after a simplifying assumption [7,8]. The simplifications are justified and if all the same numbers are entered into the equations, they all yield the same result. Several intuitive and useful messages are inherent in these equations:


-Increases in SHBG or Ka decrease free E2.

-Increments in an existing excess of total E2 over SHBG all go to free E2.

-When total E2 is small compared to SHBG, the fraction bound depends only on the Ka and SHBG concentration.

- When SHBG and E2 are more or less equal the fraction of E2 bound depends on [total E2], [SHBG], Ka and on [total E2]/ [SHBG].







2. Free E2: calculate or measure?

2.1. Calculate
Substantially more effort has gone into examining the vagaries of free T than free E2. Although there are distinct differences in estimating free T and free E2, the general approaches are the same and, as appropriate, we will cite papers dealing with the approach to calculating/measuring free T. To calculate free estradiol one must first have an accurate measure of total estradiol, SHBG, albumin, and the appropriate Ka’s. The difficulties with, and problems of, assaying estradiol constitute a large part of this special issue and I would simply emphasize that without a proper assay for total estradiol, there can be no accurate determination of free estradiol. SHBG can be measured, either by its ligand binding capacity, by immunoassay or, more recently by mass spectrometry [9]. Commercial methods are available for its immunoassay. At least some of those assays have been standardized against the binding capacity of a standard SHBG preparation obtained from the WHO. There are however problems with the standard; its binding capacity is lower than the previous standards, and its Ka for the SHBG steroid interaction is also lower [10]. Further, one need be sure that the standard’s binding activity is equal to its immunologic activity as the two activities must be proven to be identical and are differentially sensitive to denaturation. Estimation of the proper association constants for E2-SHBG and E2-albumin are problematic (Table 1). As can be seen, there is a >3-fold difference in the highest vs. the lowest Ka for estradiol-SHBG and an almost 2-fold difference in the highest vs. the lowest Ka for estradiol–albumin. Thus, depending on the choice of Ka, widely discrepant values would be calculated. Finally, it is possible for a variety of other steroids to compete for binding with E2. This would raise the concentration of free estradiol, but is not ordinarily taken into account in calculated values. For the most part, this does not appear to be a problem in non-pregnant women (in whom competing steroids do not circulate in sufficiently high concentrations to increase free estradiol) but can yield incorrect results in the presence of unsuspected competitors or in known situations, such as male plasma, where the concentration of T far exceeds that of estradiol and displaces it from SHBG binding sites. If competitors are present and measured, the overall binding equations can be altered and appropriate corrections can be made [11]. Despite all these caveats, calculation is the prevalent way that free E2 is estimated. For those agreeing on the various measurements, and using the same Ka’s, the results can be comparable, thus giving the false impression of ‘‘accuracy by the majority.’’ Finally, it has been suggested that the binding of ligands to SHBG is allosteric and that the two binding sites on the homodimer do not have the same Ka. Occupancy of one of the sites on the homodimer is posited to alter the Ka of the other. Modeling based on this concept is said to result in calculated values in better agreement with careful measurements of free estradiol than previous models [12].





2.2. Measure
As stated above, free E2 in plasma is a theoretical construct that follows from the Law of Mass Action which was formulated by chemists in the late 1800’s and ‘‘explains and predicts behaviours [sic] of solutes in dynamic equilibrium.’’ Acceptance of the Law of Mass Action does not necessarily imply that all the components of an equilibrium mixture can be accurately measured or, indeed, how it is to be done. Whatever method is used ideally should not: disturb the equilibrium that exists in vivo; change the environment that exists in vivo (ionic strength pH, etc); and be accomplished at the same temperature that exists in vivo. The two methods that best approximate these criteria are equilibrium dialysis and centrifugal ultrafiltration (see Table 2).



2.2.3. Choose a method
The choice is guided by both convenience/ease and the desire to obtain the answer most likely to coincide with the true value of free E2. Whichever method one chooses, E2 must be accurately and reproducibly measured; this is required whether one calculates or measures. Once having conceded the ability to measure E2, then the calculation offers the advantages of simplicity and economy. SHBG and albumin are easily measured and the calculation is automated. On the negative side: there is disagreement about the proper Ka’s and SHBG is not properly standardized/harmonized. In spite of these potential hazards, a number of communications have claimed excellent agreement between calculated and measured values for free testosterone [13,16,20] and free estradiol [13]; however, a number of publications find disagreement between measured and calculated values [21–23]. In addition the calculation of free E2 has been compared to measured values, and found to be satisfactory, in only a small sample of postmenopausal patients [13]; the authors caution against using the calculated value in other populations. Moreover, it should be recalled that E2 is bound to SHBG 2–3-fold less tightly to SHBG than is testosterone, rendering the assumption of a fixed value for albumin unacceptable until the appropriate calculations and experiments are at hand. This is still an unsettled issue and no irreversible recommendations as to the best way to proceed can be issued at this time.

Jesus. Things just got a lot more complicated! But amazing excerpt. Idk where you found it, but thanks so much for posting it. I’m definitely saving all that somewhere. That excerpt goes into amazing detail on calculated vs measured free E2. It went over so many things I had no clue about. Super good read. Just sucks that even after they went over everything, they still weren’t really able to conclusively give an answer on which is better, calculated E2 or measured free E2. My personally opinion though, after reading the whole thing, is it’s better to go with measured free E2. Thanks again for posting it, awesome info!

 

[Vince Carter]

People post here E2 results all the time, usually sensitive E2 essays . They don't refer to it as "total E2" , but that's what they are.

I'm not sure how to even respond to that. I think that you'd be really well served to read a lot more on this forum than you post.

 

[Gman86]

So I’m unfortunately pretty lazy at the moment, and not near my computer. But I’ll post a bunch of my values, and you guys can plug the numbers into the spreadsheet and see what you get for results, and can compare them to my actual measured free E2 if u’d like. I’ll probably have time later to do this myself, and will edit this post with the results if I do.

6-16-17
E2 NOT Sensitive - 71
E2 Free - 1.88 (0.2-1.5)
SHBG 44 (10-50)
Albumin - 4.4g/dL


8-15-17
E2 Sensitive - 8
E2 NOT Sensitive - 13
E2 Free - 0.28 (0.2-1.5)
SHBG 51 (10-50)
Albumin - 4.6g/dL


12-13-17
E2 Sensitive - 9
E2 NOT Sensitive - 13
E2 Free - 0.28 (0.2-1.5)
SHBG 36 (10-50)
Albumin - 4.4g/dL


7-9-18
E2 Sensitive - 46
E2 NOT Sensitive - 27
E2 Free - 0.58 (0.2-1.5)
SHBG 47 (10-50)
Albumin - 4.6g/dL


8-24-18
E2 Sensitive - 57
E2 NOT Sensitive - 56
E2 Free - 1.35 (0.2-1.5)
SHBG 41 (10-50)
Albumin - 4.3g/dL


10-23-18
E2 Sensitive - 58
E2 NOT Sensitive - 68
E2 Free - 1.48 (0.2-1.5)
SHBG 44 (10-50)
Albumin - 4.6g/dL


12-6-18
E2 Sensitive - 10
E2 NOT Sensitive - 15
E2 Free - 0.33 (0.2-1.5)
SHBG 45 (10-50)
Albumin - 4.7g/dL

 

[lowTengineer]

I get it, though here, we don't test Total Estradiol so it get's kind of to being a moot point for US guys but clear and valid point for you that don't have the access to these tests.

People post here E2 results all the time, usually sensitive E2 essays . They don't refer to it as "total E2" , but that's what they are.

I'm not sure how to even respond to that. I think that you'd be really well served to read a lot more on this forum than you post.

You really doubled down on your argument, I'm curious where this is headed. What do you say is the difference?

 

[Nelson Vergel]

There's been a lot discussion recently in Excelmale on wanting to test for Free E2 and the relatively high cost of this test. There are online calculators which calculate an estimate of Free T based on Total T, SHBG and Albumin. However there doesn't appear to be an online calculator for estimating Free E2.

I researched the topic and found an article from 2010 by Norman Mazer, Ph.D, who created an Excel spreadsheet for calculating Free T, Free E2, Free DHT and others. The first tab in the spreadsheet is titled "user interface" and you input there the values of Total T, Total E2, Albumin and SHBG and the spreadsheet calculates the Free values.

I modified the spreadsheet slightly to make it more user friendly - changed the titles, highlighted the fields to be inputed in Blue and the results in green, and added ability to input data in nmol/L and pmol/L units and to auto convert these units. You can download the modified spreadsheet .

Enjoy!

I will look into this.

I love creative solvers! Thank you so much.

 

[rafapark]

I get it, though here, we don't test Total Estradiol so it get's kind of to being a moot point for US guys but clear and valid point for you that don't have the access to these tests.

My head is spinning with all this. I am all for testing free estradiol instead of calculating it and I will test it next time, but what is the "good range" that free estradiol should be at then?

 

[BenM]

Thanks Simon. I’ll have a look at this later today - we don’t test total E here either (only free) so as a high SHBG guy I’m curious to see how the calculations look.

 

[Simon7]

I used Gman86's values which he posted above to compare his Free E2 measurement vs. the calculated Free E2 by the spreadsheet.

For all of Gman86's tests except for the first one he provided values for both sensitive E2 and NON sensitive E2, so I calculated Free E2 twice for each of test based on the sensitive + NON sensitive E2 result.

Here are the results:

Analysis:

1. Twelve out of the thirteen results of calculated Free E2 (with the exception of the result with the 78% difference) provided close approximation of measured Free E2 for the evaluation of where the Free E2 result lies on on the normal range of [0.2.....1.5] - which is the evaluation used to decide on future treatment dosage

2. The difference between the measured and calculated Free E2 result was much smaller (average difference of only 5.8%) when the calculation was based on the NON sensitive E2 result (vs. average difference of 30.5% when based on sensitive E2 results). One possible explanation for this is that perhaps the Free E2 test used was a NON sensitive test as well. Gman86 can you provide a link to the lab Free E2 test code that you used?

 

[rafapark]

I used Gman86's values which he posted above to compare his Free E2 measurement vs. the calculated Free E2 by the spreadsheet.

For all of Gman86's tests except for the first one he provided values for both sensitive E2 and NON sensitive E2, so I calculated Free E2 twice for each of test based on the sensitive + NON sensitive E2 result.

Here are the results:

View attachment 6508


Analysis:

1. Twelve out of the thirteen results of calculated Free E2 (with the exception of the result with the 78% difference) provided close approximation of measured Free E2 for the evaluation of where the Free E2 result lies on on the normal range of [0.2.....1.5] - which is the evaluation used to decide on future treatment dosage

2. The difference between the measured and calculated Free E2 result was much smaller (average difference of only 5.8%) when the calculation was based on the NON sensitive E2 result (vs. average difference of 30.5% when based on sensitive E2 results). One possible explanation for this is that perhaps the Free E2 test used was a NON sensitive test as well. Gman86 can you provide a link to the lab Free E2 test code that you used?

I only see one free estradiol test in the labcorp test menu: 500649

 

[Gman86]

I use quest only. I think it’s 36169. I get the Estradiol, Free, LC/MS/MS done, but could only find the code for the regular Estradiol, free.

 

[Gman86]

I used Gman86's values which he posted above to compare his Free E2 measurement vs. the calculated Free E2 by the spreadsheet.

For all of Gman86's tests except for the first one he provided values for both sensitive E2 and NON sensitive E2, so I calculated Free E2 twice for each of test based on the sensitive + NON sensitive E2 result.

Here are the results:

View attachment 6508


Analysis:

1. Twelve out of the thirteen results of calculated Free E2 (with the exception of the result with the 78% difference) provided close approximation of measured Free E2 for the evaluation of where the Free E2 result lies on on the normal range of [0.2.....1.5] - which is the evaluation used to decide on future treatment dosage

2. The difference between the measured and calculated Free E2 result was much smaller (average difference of only 5.8%) when the calculation was based on the NON sensitive E2 result (vs. average difference of 30.5% when based on sensitive E2 results). One possible explanation for this is that perhaps the Free E2 test used was a NON sensitive test as well. Gman86 can you provide a link to the lab Free E2 test code that you used?

Holy crap, thank you so much for taking the time to do all that! Awesome work! Very astute observation as well with the rationale why the calculated E2 tests seem to correlate more with my non sensitive E2 results than my ultrasensitive E2 results. I looked back at all my quest results, and even though I order the Estradiol, Free, LC/MS/MS test each time, I think they basically just run the standard Estradiol, Free for some reason. I’ll post pics so you can see what I’m talking about. In the grey is the test you request, and then the white is the test they run, and the results. You can see that all the other tests, the grey matches the white, like with the E2 ultrasensitive, IGF-1, and cortisol. They all have the LC/MS/MS in the test run and the results. With the Estradiol, Free, LC/MS/MS, it’s in the grey box correct, but the free E2 they ran doesn’t have the LC/MS/MS after it, which makes me think you are correct, and that I’ve only been getting the standard Estradiol, Free done, which might match up better with the non-sensitive total E2 test.

 

[Gman86]

And the reason that there was a 78% difference in that one result, is because for some reason there was a big difference in my E2 sensitive and non-sensitive results, and I pretty much knew one of the test results was wrong. I was leaning towards the 27 being closer to what was accurate, based off of my free E2 result. I felt like my free E2 should of been a little higher if my total E2 really was 46. But now I know for sure that the 27 is probably the accurate one, based off of your calculated results. So thank you for that.

E2 Sensitive - 46
E2 NOT Sensitive - 27
E2 Free - 0.58 (0.2-1.5)
SHBG 47 (10-50)
Albumin - 4.6g/dL