Luteinizing Hormone (LH), serum and plasma

Alternate test name

Gonadotropins include both FSH and LH

Lab area

Clinical Biochemistry - General

Method and equipment

Equipment : Roche Cobas Pro e801

Method : Sandwich principle. Total duration of assay: 18 minutes.
▪ 1st incubation: 12 µL of sample, a biotinylated monoclonal LH‑specific antibody, and a monoclonal LH‑specific antibody labeled with a ruthenium complex form a sandwich complex.
▪ 2nd incubation: After addition of streptavidin-coated microparticles, the complex becomes bound to the solid phase via interaction of biotin and streptavidin.
▪ The reaction mixture is aspirated into the measuring cell where the microparticles are magnetically captured onto the surface of the electrode. Unbound substances are then removed with ProCell II M. Application of a voltage to the electrode then induces chemiluminescent emission which is measured by a photomultiplier.
▪ Results are determined via a calibration curve which is instrument specifically generated by 2‑point calibration and a master curve provided via the cobas link.

Expected turn-around time

STAT/ Urgent: 4 hours Routine: 24 hours

Specimen type

Serum and Plasma Lithium Heparin

Specimen requirements

150 uL

Storage and transportation

Frozen

Shipping information

The Hospital for Sick Children

Rapid Response Laboratory

555 University Avenue, Room 3642

Toronto, ON

Canada

M5G 1X8

Phone: 416-813-7200

Toll Free: 1-855-381-3212

Hours: 7 days/week, 24 hours/day

Requisition

Luteinizing Hormone (LH), serum and plasma - requisition

Background and clinical significance

LH is a dimeric glycoprotein hormone secreted by the anterior pituitary in response to hypothalamic gonadotrophin releasing hormone. The α-subunit is common to other glycoprotein hormones, while the β-subunit, which confers biological activity, has some homology with that of human chorionic gonadotrophin. During the menstrual cycle, follicle stimulating hormone (FSH) stimulates growth of the ovarian follicle which, when mature, ovulates in response to a surge of LH and, to a lesser extent, of FSH. Ovarian steroids are the primary negative feedback control for LH secretion. At menopause, reduced ovarian negative feedback results in elevated LH concentrations. LH concentrations also tend to be elevated in women of pre‑menopausal age who experience ovarian failure, or whose ovaries failed to mature during puberty.