Laboratory parameters of the 1st order – obligatory laboratory tests.
- IGF-1 (insulin-like growth factor).
- IGFBP-3 (insulin-like-growth-factor-binding-protein-3)
Laboratory parameters 2nd order – depending on the results of the history, physical examination, etc. – for differential diagnostic clarification.
- Hormone diagnostics: DHEA-S, total testosterone, SHBG (sex hormone-binding globulin), FSH, prolactin, TSH, estradiol if necessary, pituitary function test (test of pituitary gland function); the insulin tolerance test is the gold standard and the most commonly used stimulation test for the diagnosis of STH deficiency in adults.
- Small blood count
- Inflammatory parameters – CRP (C-reactive protein) or ESR (erythrocyte sedimentation rate).
- Urine status (rapid test for: pH, leukocytes, nitrite, protein, glucose, ketone, urobilinogen, bilirubin, blood), sediment, if necessary urine culture (pathogen detection and resistogram, that is, testing suitable antibiotics for sensitivity / resistance).
- Fasting glucose (fasting blood glucose), if necessary oral glucose tolerance test (oGTT).
- Liver parameters – alanine aminotransferase (ALT, GPT), aspartate aminotransferase (AST, GOT), glutamate dehydrogenase (GLDH) and gamma-glutamyl transferase (gamma-GT, GGT), alkaline phosphatase, bilirubin.
- Renal parameters – urea, creatinine, cystatin C or creatinine clearance, if necessary.
- Atherosclerosis parameters:
- Total cholesterol, LDL cholesterol, HDL cholesterol.
- Triglycerides
- Homocysteine
- Vitamins D3, B6, B12, folic acid, trace elements selenium and zinc.
- Test for occult (not visible) blood in the stool.
- PSA (prostate specific antigen)
Other notes
- Since growth hormone is predominantly released nocturnally, the measurement of STH and hGH, respectively, is not very useful.
- IGF-1, a somatomedin or mediator of growth hormone action produced by the liver in response to pituitary STH secretion, is a bio-chemical marker of STH secretion status and as such IGF-1 generally correlates well with STH secretion in healthy individuals. However, because IGF-1 concentrations do not always correlate with STH secretion status, particularly in the presence of STH deficiency, determination of serum IGF-1 concentrations alone is not sufficient to diagnose STH deficiency. Accordingly, a “normal” serum IGF-1 concentration is not an exclusion criterion for possible STH deficiency and initiation of STH replacement therapy. Thus, serum IGF-1 concentration is not only an important additional indicator of STH secretion status, but also an essential parameter in the monitoring of STH substitution therapy.
- In this context, IGFBP-3 determination can also provide further information about the individual STH secretion profile, but it is not a necessary parameter in the determination of STH secretion status and is also of potential importance for monitoring therapy in general only if complications arise in the implementation of therapy, such as deviations in the individual response to STH administration.
- Therefore, determination of IGF-1 and its major binding protein (IGFBP-3) has been shown to be favorable as an indicator of overall growth hormone effect. IGF-1 levels < 180 ng/ml indicate hGH deficiency.
Caution.
- Hormone findings should always and only be assessed in the context of clinical symptoms.
- In principle, the same assay method must always be used for the determination of a hormone as well as for the implementation of therapy.
- Please note the different standard values of the various laboratories.
