On 23/12/2003, at 16:27, Kermaline J. Cotterman wrote:

> And conversely, when the TSH result is low, it means the feedback to
> the
> pituitary indicates the level of thyroid is within normal limits, and
> therefore, no need to stimulate extra production.

Only if the pituitary gland is in good working order. A low TSH can
also mean that a person is experiencing pituitary failure (eg Sheehan's
syndrome), and in this situation the T4 would be expected to be low
also, rather than the high-T4, low-TSH situation in hyperthyroidism.
Hence using TSH as a lone thyroid function test is useless if there is
a possibility of pituitary hypofunction; you need the full thyroid
function tests.

Lara Hopkins

             ***********************************************

To temporarily stop your subscription: set lactnet nomail
To start it again: set lactnet mail (or digest)
To unsubscribe: unsubscribe lactnet
All commands go to [log in to unmask]

The LACTNET mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software together with L-Soft's LSMTP(R)
mailer for lightning fast mail delivery. For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html