Standard Ranges for Test lab results (Why the differences?)

[Pumpedd]

I’m not the smartest science guy, so was wonder why all labs can’t use the same standard range? For some reason I see different ranges such as “Testosterone Standard range 250 – 1100” or “Testosterone Standard range >200”? Is a test reading of 293ng/dl not the same for both standard ranges?
Thanks,
Pumpedd

 

[cashout]

I’m not the smartest science guy, so was wonder why all labs can’t use the same standard range? For some reason I see different ranges such as “Testosterone Standard range 250 – 1100” or “Testosterone Standard range >200”? Is a test reading of 293ng/dl not the same for both standard ranges?
Thanks,
Pumpedd

"Standard Ranges" are established by collecting a random sample of a population of interest and computing a mean for the random sample. Assuming the sample taken from the population is sufficiently large and represents a normal distribution per the Central Limit Theory, researchers infer that the sample is representative of the entire population, given some sampling error.

Then the researcher computes 3 standard deviations in either direction - above and below the computed mean - volia - that creates lower and upper bounds of what one would expect to find in 99.5% of the population.

So, 250 - 1100 would represent the lower and upper bound of -/+ 3 standard deviations of a sample mean.

The lab ranges vary based on which sample of the population they basis their ranges upon.

 

[Pumpedd]

Cashout, Thanks for explaining the standard range, that makes sense. I believe this standard deviation stuff is statistics and I failed statistics twice in college before finally passing it with a C (C’s get degrees).

Maybe I should rephrase my question.

Seems like each lab has their own standard range for testosterone. Shouldn’t all labs be using the same range? You mentioned “The lab ranges vary based on which sample of the population they basis their ranges upon.” Shouldn’t all the labs use the same sample of the population?

 

[cashout]

“The lab ranges vary based on which sample of the population they basis their ranges upon.” Shouldn’t all the labs use the same sample of the population?

Ideally, yes but in many cases there are proprietary (ownership) rights associated with data and using other researchers data - read that as - they would have to pay a royalty.

 

[ecdysone]

Laboratory reference ranges are typically based on the 2 SD (95%) range from literature studies of fairly large populations.

The larger labs do millions of tests and they often "mine" their own data and develop a lab-specific ref. range.

With testosterone, the method used for analysis can have a large effect on the mean level and therefore the reference range. For example, labs using LC/MS/MS will have different ranges than those using more traditional methods.

With some tests, for example CBC's, the values are historically accepted and each new lab will just use what everyone else has used for years. With newer tests or methods, each lab will typically have difference ranges and then finally, some tests (for example cholesterol) are based more on politics and will only vary from country to country.

If one precisely wanted to know how a lab developed it's ref. range you would have to contact a technical person who worked there and ask them either what literature study they referenced or whether they are using internally-generated ranges.

 

[lcplblazer]

Not to get off topic, but I was also wondering how lab's got their ranges, or more so about how MY labs got THEIR ranges...

My question is, would a lab having a "normal" range for total test in the 185-650ng/dl seem kind of odd? (This is the range given for my TT). Compared to just about every lab range I've seen posted on here (and other sites), this range seems to be on its own program.

Maybe I'm missing something, but doesn't it seem like "my lab" is setting the standards a little low?

 

[ecdysone]

What's the lab name?

 

[lcplblazer]

What's the lab name?

I dont recall. When I get the print off I'll start my own topic with full stats and ranges.