Pathology Handbook



Insulin-like Growth Factor 1, 

Clinical Indications

Screening for acromegaly. An elevated IGF-1 in a patient with the appropriate clinical picture is diagnostic. Occasionally acromegalics may have a normal IGF-1 level at diagnosis so a growth hormone suppression test remains the definitive diagnostic test.
Follow up of treatment for acromegaly. IGF-1 should be measured annually along with growth hormone.  Elevated IGF-1 with normal growth hormone levels may indicate a need for further lowering growth hormone levels.

Request Form

Request on ICE


On request

Specific Criteria

Requested by Consultant Endocrinologists or if agreed with Consultant Biochemist.

Turnaround Time





2 ml


Vacutainer gold top


Samples must be transported to laboratory immediately.Patients must be bled at Southend Hospital.

Lab Handling

Separate immediately and freeze at minus 20C. Sample sent to referral laboratory (Guildford).

Causes for Rejection

Unlabelled or incorrectly labelled sample; not meeting specific criteria for analysis; delay in sample reaching laboratory.

Reference Range

Please note the IGF1 assay changed from Siemens to IDS iSYS on the 01/02/2013 and the units have changed from ng/L to nmol/L since this date.

Please refer to the laboratory report for the reference range as these are now age and sex related.