Far different reference ranges

[RickB]

I've been off trt for over three months and had blood work done at my urologist. They're using Roche now instead of LabCorp. One question comes up right away, and that's how the two estradiol methods differ. Because even though both labs use pg/mL, the reference ranges are drastically different.

LabCorp is 7.6 to 42.6
Roche is 41 to 91.9

I am sure that the methodology is the specific cause for the difference in reference ranges, rather than differing ideas about what range is normal. I have always had low estradiol without trt, around 6. Now with Roche I am still low at 19.5. I have little doubt that 6 at LC and 19.5 at Roche are roughly the same, but can anyone explain the difference in the testing?

(inb4 madman tells me it doesn't matter, because both assays are piss poor.)

 

[Systemlord]

The Roche method is fine if you don’t have an elevation in C-reactive protein, a marker for inflammation, which if elevated, will falsely elevate the estrogen value.

The sensitive method is more accurate provided the technician skill is high, otherwise the accuracy can be lower.

So if you don’t have an elevation in C-reactive protein, the Roche method may be better and more consistent.

We don’t live in a perfect world, each method has a drawback.

 

[Systemlord]

Regardless of the normal lab ranges, you don’t want E2 <20 period!

 

[tareload]

Performance of Direct Estradiol Immunoassays with Human Male Serum Samples

AbstractBACKGROUND. Steroid immunoassays originally required solvent extraction, chromatography, and structurally authentic tracers to avoid interference f

academic.oup.com

Performance of Direct Estradiol Immunoassays with Human Male Serum Samples | Oxford Academic

academic.oup.com

The x axis is the reference method (LC-MS), and the y axis represents the measurements from 1 of 5 commercial E2 immunoassays (A–E). The diagonal line represents the line of identity, the heavier line the Passing–Bablok regression line, and the outer dotted lines the 95% confidence limits.

A, Siemens ADVIA.

B, Siemens IMMULITE 2000.

C, Abbott ARCHITECT.

D, Roche cobas.

E, Beckman Coulter Access

The reasons for these discrepancies are related to the origins of steroid immunoassays, which were developed in 1969 (29) but delayed for a decade after the invention of peptide immunoassay because additional steps were required to adapt immunoassay methodology to valid measurement of nonimmunogenic small molecules such as steroids. Developing steroid-specific antibodies required conjugating steroids as haptens to larger immunogenic carrier proteins via small multivalent reactive bridge compounds. However, this made steroid antibodies that were epitope “blind” to the conjugation site, allowing for undesirable cross-reactivity with structurally related steroids (e.g., structurally related steroid precursors, metabolites, and conjugates produced by phase II metabolism). The original in-house steroid immunoassays developed in the 1970s used solvent extraction, chromatography, and structurally authentic (H3, C14) tracers, a triplet of validity criteria for steroid immunoassay that removed structurally related steroids as well as nonspecific matrix interference in the immunoassay reactions. In the ensuing decades, E2 immunoassays were commercialized primarily to monitor ovarian responses to gonadotropin stimulation, where excessive serum E2 response was a risk indicator for dangerous overdosage effects such as high-order multiple pregnancies and/or life-threatening ovarian hyperstimulation syndrome. However, making a quantal distinction between dangerously high E2 concentrations (>2000 pmol/L) and typical premenopausal concentrations (200–800 pmol/L) did not require quantitative accuracy at physiological E2 concentrations. Subsequently, ultrasound monitoring of follicular growth has reduced the importance of this application of serum E2 immunoassays. The subsequent growing demand for steroid immunoassays in clinical practice and research resulted in assay simplification to adapt steroids into semi-automated multiplex platforms and 1-plate/tube kit formats, preferred by routine pathology and research labs, respectively. This simplification eliminated preassay purification steps (extraction, chromatography) as well as β-scintillation counting, with the latter forcing the replacement of structurally authentic steroid tracers with bulky conjugated steroids, which allowed for more convenient nonradioactive assay readouts. However, eliminating the triplet of validity criteria (preassay extraction and chromatography, authentic tracers) sacrificed the specificity of E2 immunoassays and revealed the vulnerabilities of direct steroid immunoassay to artifacts from steroid cross-reactivity and matrix interference. Although the original validated steroid immunoassays are now confined to a few long-established laboratories, there is evidence that some but not all the limitations of direct E2 immunoassays can be overcome by preassay solvent extraction (12, 28). However, since our study did not include any classical (indirect) estradiol immunoassays, it is not clear whether meeting the original triplet validity criteria is sufficient to overcome all limitations of direct E2 immunoassays, and it remains possible that suboptimal antibody specificity could also contribute to the nonspecificity of steroid immunoassays

Read the discussion or click above to show the spoiler. That's a mouthful. Aren't immunoassays fun?

 

[tareload]

Regardless of the normal lab ranges, you don’t want E2 <20 period!

Why? 10 or 15 or 19 pg/ml just don't cut it?

I can find no scientific or factual basis for thar statement. Can you?

 

[Systemlord]

Why? 10 or 15 or 19 pg/ml just don't cut it?

Maybe for an outlier who is sensitive to estrogen 15 pg/mL would be perfectly fine, and I know for a fact we have some members here where this is the case, but I recall a couple of members diagnosed with osteoporosis with an estrogen value at 16 alongside a low-T value.

So I prefer to play it safe.

 

[tareload]

The Roche method is fine if you don’t have an elevation in C-reactive protein, a marker for inflammation, which if elevated, will falsely elevate the estrogen value.

The sensitive method is more accurate provided the technician skill is high, otherwise the accuracy can be lower.

The OP's question was regarding the ref range for two immunoassays. The ref range above for the Labcorp test is the ECLIA method. Your answer implies the Labcorp assay above is LCMS. It is not.

 

[tareload]

The Labcorp normal ranges for sensitive estrogen is 20-35.

Labcorp LCMS estradiol ref range is 8 to 35 pg/ml.

140244: Estradiol, Sensitive, LC/MS | Labcorp

Labcorp test details for Estradiol, Sensitive, LC/MS

www.labcorp.com

Mayo LCMS is 10 to 40:

EEST - Overview: Estradiol, Serum

All applications that require moderately sensitive measurement of estradiol: -Evaluation of hypogonadism and oligo-amenorrhea in females -Assessing ovarian status, including follicle development, for assisted reproduction protocols (eg, in vitro fertilization) -In conjunction with luteinizing...

www.mayocliniclabs.com

Look up ARUP as well or any reference laboratory in the US.

https://www.brighamandwomens.org/assets/bwh/research/pdfs/lcms-estradiol-estrone_revised_070113.pdf

See a pattern?

Notice 20> 8 or 10.

 

[tareload]

So I prefer to play it safe.

Thank you for removing the error on lower reference range of 20 pg/ml you had previously posted. This is how we avoid going over the same stuff year after year after year....

 

[Systemlord]

Labcorp LCMS estradiol ref range is 8 to 35 pg/ml.

Not on my lab report.

 

[tareload]

Not on my lab report.

Post it up / order code?

Your report is for LCMS E2?

From above...

140244: Estradiol, Sensitive, LC/MS | Labcorp

Labcorp test details for Estradiol, Sensitive, LC/MS

www.labcorp.com

 

[Systemlord]

Post it up / order code?

Your report is for LCMS E2?

I just looked on my Labcorp portal, you’re right, I was wrong. I swear I have seen labs with 20-35 before from Labcorp or maybe Quest that were from a member.

 

[tareload]

I just looked on my Labcorp portal, you’re right, I was wrong. I swear I have seen labs with 20-35 before from Labcorp or maybe Quest that were from a member.

Hmmm, I've never seen an LCMS assay with lower reference range that high. For example, Quest:

Quest Diagnostics: Test Directory

testdirectory.questdiagnostics.com

ARUP:

Estradiol (Adult Males, Children, Postmenopausal Females, or Individuals on Estrogen-Suppressing Hormone Therapy) | ARUP Laboratories Test Directory

Use this mass spectrometry test to measure a wide range of estradiol concentrations. Most useful when low estradiol concentrations are expected, regardless of the patient’s sex assigned at birth. Use to monitor estradiol in individuals on estrogen-suppressing hormone therapies (eg, aromatase...

ltd.aruplab.com

Very consistent male reference ranges among the US reference laboratories.

Quest always appears the odd duck and as @madman has noted multiple times they still aren't part of Host standardization list.

 

[tareload]

No one wants to talk preassay extraction or finer points of matrix effects? Bummer. This thread had so much promise.

Laughing/crying emoji here.

Good stuff RickB.