Gn-RH test (LH-RH test)
(Gonadotropin-releasing hormone test)
Indication |
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Principle | The LH-RH test in children with a dose of 50 µg/m² body surface (max. 100 µg absolute) and 100 µg in adults checks the gonadotropic reserve capacity of the pituitary gland. In children, the test with lower doses of LH-RH (e.g. 10 µg, max. 25 – 30 µg absolute) corresponds to a sensitivity test. |
Evaluation parameters | LH, FSH |
Material | Serum before (0 min) and 15, 30 and 45 min after Gn-RH administration. In general, the LH-peak occurs 30 min and the FSH-peak 45 min after Gn-RH stimulation. |
Procedure | Discontinue sexual hormones (testosterone or oral anti-conception) at least 6 weeks prior to the test. As far as there is a cycle, the test should take place during the follicle phase.
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Evaluation | Women: Pathological (hypogonadotropic hypogonadism): LH increase < 20 IU/l Grey area: LH increase > 20 IU/l with absolute LH values < 40 IU/l Inconspicuous: LH rise > 20 IU/l with absolute LH value > 40 IU/l
Girls: Depending on the stage of puberty. Furthermore, a differentiation between (benign) premature thelarche and (true) central precocious puberty can be achieved by determining the LH/FSH ratio: Premature thelarche: LH/FSH ratio < 1.0 Central precocious puberty: LH/FSH ratio > 1.0
Men: An LH increase of at least 1.5 times indicates that the gonadotropic axis is intact. FSH is of secondary importance in this context. Often, only little or no stimulation is possible.
Boys: Depending on the stage of puberty. For the differentiation of a hypophyseal hypogonadism from a hypothalamic hypogonadism a so-called “pituitary gland training” by pulsatile Gn-RH administration via a mini infusion pump before LH-RH stimulation can be helpful. The pituitary gland can be stimulated in hypothalamic hypogonadism, but it is not possible to stimulate it in hypophyseal causes. |
More Results for the letter G
- Gastrin stimulation test
- Secretin provocation test
- GH-RH test
- Growth hormone-releasing hormone
- Glucagon stimulation test
- Gn-RH test (LH-RH test)
- Gonadotropin-releasing hormone test
- Growth hormone