Re: comparing labs with different ref ranges

[Guest guest]

Martha,

My experience

has been when the ref ranges changes it is usually because the lab processing

the blood is different. I did not see your first post…sorry. I don’t

know if they might have been sent out to different places to be processed or

what? Is there any indication on the paperwork you have?

Maybe they even

updated the machinery since that time.

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[Guest guest]

>

> I apologize if I'm violating netiquette by re-posting my question

from

> Friday, but here goes:

> Can anyone give me guidance on comparing Alk Phos levels when the

> reference ranges have changed? Is there any significance to the

> following change?

>

> 7/7/06 141, normal range 20-125

> 2/14/06 181, normal range 50-136

>

> Also the 7/7 labs were broken down into a liver fraction and bone

> fraction, which were in the normal range, as well as two others that

> were both zero. Is this a good sign?

>

For some reason I thought someone had already answered your question

but looking back in the posts I see that is not the case.

Different reference ranges between labs is normal based on how they

process the sample. The difference you mention above is

statistically insignificant, especially with Alk Phos which is

somewhat variable and can have large changes depending on when the

blood was drawn. You could have labs drawn the next day and see a

somewhat different result than the previous day for no apparant

reason.

The increase from 141 to 181 is not a significant increase and if the

other lab values did not go up significantly as well I would not

worry too much about it. What would be more significant would be

over the course of several lab tests you saw a steady trend upward

with correlating increase in other LFT values.

I have never seen an Alk Phos test that gave a further breakdown as

you describe so I can't really address that question. Perhaps

someone else can.

in Seattle

UC 1991, PSC 2001

[Guest guest]

A good explanation of lab reference ranges, how they are determined

and should be used can be found at:

http://www.labtestsonline.org/understanding/features/ref_ranges.html

Alkaline phosphatase is an enzyme found in the cells that make bone,

as well as liver cells, so determining the source of elevated Alk

Phos can help pinpoint the problem area. Because Alk Phos is

released by growing bones, a child or pregnant woman will have high

Alk Phos level and the reference range is adjusted for age and child

bearing condition (if these are known).

There are multiple varieties of ALP, called isoenzymes. Different

types of isoenzymes, each with different structures, are found in

different tissues (for example, liver and bone ALP isoenzymes have

different structures) and can be quantified separately in the

laboratory. To differentiate the location of damaged or diseased

tissue in the body, ALP isoenzyme testing must be done.

http://www.nlm.nih.gov/medlineplus/ency/article/003470.htm

I agree with that the changes that you report are not

significant, and suspect the change in reference range was due to a

new testing procedure at the lab you use. The use of the isoenzyme

testing helps to identify which area is contributing to your overall

slightly elevated Alk Phos. Since bone alk phos is in the middle of

its range and liver is near the top, it is probably (SURPRISE!) the

liver that is causing the elevated readings.

Regards,

Tim R

[Guest guest]

Alkaline phosphatase - an enzyme used to help identify liver dysfunction.

Although AP levels alone do not define hepatic problems, when supported by

other clinical signs, may help confirm a diagnosis, especially when bile duct

obstruction is suspected. AP is also essential in bone remodeling, the process

by which bone tissue is continually responding to the stresses of exercise.

Increased serum levels are a general indication of osteoblast

activity, the cells involved in building new bone tissue. When high levels of

GGTP and/or bilirubin accompany serum increases of

AP, a follow-up examination for liver dysfunction is very highly recommended.

Barb in Texas

[Guest guest]

Martha

I am not the expert on labs, but what I do know is that each lab lists normative ranges because of differences in equipment, procedures, etc. The other thing is that even within one lab, 300 is not 3 times as "bad" as 100, etc., the scale is not the typical linear scale we are all so accustom to. Poof! now you know all I do!

Bestjd, 45 goin to 46UC 1973, Jpouch 2000, Chronic Pouchitis 2001, PSC 2004, Stage 3Southern, IL