Hi Jeff,
I've always believed that correction (or adjusting as was pointed out to me
when I posted a question on the subject!) was less valid for high albumin
levels than for low.
But either way, I don't understand your colleagues logic. If albumin is high
(ie > 40) then corrected serum calcium will be lower than total calcium.
Don't know about a specific formula for children but the reference I tend to
use for children: "Clinical Biochemistry and the sick Child" by Clayton and
Round has no reference to such correction. That said, an older text
"Paediatric Chemical Pathology" by Clayton, Jenkins and Round (1980) quotes
a calcium reference range for "childhood" of 2.13-2.62 mmol/l (no
correction) in fasting capillary samples. It then quotes "corrected"
non-fasting venous calcium ranges of 2.28-2.60 (boys) and 2.27-2.59 (girls)
noting "the correction for specific gravity or albumin was applied for the
older boys and girls because such factors as postural changes or venous
occlusion may give rise to variations in plasma protein levels and calcium
is in part protein bound". Refs quoted:
Dent CE. BMJ 1962; 2:1419; Round JM. BMJ 1973; 3:137.
Regards
Joe
Dr JP Begley
Clinical Biochemistry
Poole Hospital
-----Original Message-----
From: Jeffrey Barron <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Wednesday, May 09, 2001 5:17 PM
Subject: Corrected calcium in childhood
We give a corrected serum calcium for both adults and children using the
formula
Corrected serum calcium = Total calcium +(( 40-Albumin) x 0.02 )
The paediatric endocrinologist has noted that a number of children have a
normal total calcium with a raised corrected calcium, due to a high albumin.
I require advice as to whether we should continue to give a corrected
calcium for children because the formula is probably adult derived. Is there
another formula for children ?
Jeff
Dr Jeffrey Barron
Consultant Chemical Pathologist
St Helier Hospital
Carshalton
Surrey SM5 1AA
UK
Tel UK 20 8296 2660
Fax UK 20 8641 2633
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