DiaMetra Free Testosterone Elisa Kit

INTENDED PURPOSE
Free Testosterone ELISA is a manual in vitro diagnostic device intended for the quantitative determination of free testosterone in human serum or plasma from an adult population. Results are to be used in conjunction with other clinical and laboratory data as an aid in the diagnosis and monitoring of disorders involving the male sex hormones (androgens).

CLINICAL SIGNIFICANCE
Testosterone is found in circulation predominantly linked to carrier proteins, the most common of which being sexhormone binding globulin (SHBG). Testosterone plays a key role in the development of primary and secondary sexual characteristics in males and is involved in the production of female sexual hormones.
Only 1 – 2% of testosterone in circulation is not bound to any protein and is biologically active – this is referred to as ‘free testosterone’ (FT). Bioavailable testosterone refers to the sum of FT and the testosterone bound to serum albumin, since it is bound with low affinity and readily able to dissociate to become available for its biological function.
In males elevated levels of testosterone are associated with several conditions such as, early (precocious) puberty, congenital adrenal hyperplasia (CAH), androgen insensitivity syndrome (AIS), steroid use and testicular or adrenal tumours. Whereas the major causes of supressed levels include Klinefelter’s syndrome, testicular damage, pituitary disorders etc. In females of all ages, elevated testosterone levels can be associated with a variety of virilising conditions including adrenal tumours and polycystic ovarian syndrome (PCOS).

PRINCIPLE OF THE METHOD
The Free Testosterone ELISA is a competitive enzyme immunometric assay (ELISA) where free testosterone (antigen) in the sample competes with the antigenic testosterone conjugated with horseradish peroxidase (HRP) for binding to the limited number of antibodies antitestosterone coated on the microplate (solid phase).
After the incubation, the bound/free separation is performed by a simple solid phase washing. Then, the enzyme HRP in the bound fraction reacts with the Substrate (H2O2) and the TMB Substrate and develops a blue colour that changes into yellow when the Stop Solution (H2SO4) is added. The colour intensity is inversely proportional to the free testosterone concentration of in the sample.

REAGENT STORAGE AND STABILITY
Store the kit at 2 – 8°C in the dark. 
The kit is stable at 2 – 8°C until the expiry date stated on the external kit label.
Once opened, the kit is stable at 2 – 8°C for 6 months.
The diluted wash solution is stable for 30 days at 2-8°C.
Important note: open the bag containing the Coated Microplate only when it is at room temperature and close it immediately after use.

SAMPLE COLLECTION AND STORAGE
The assay should be performed using serum (standard sampling tubes or tubes containing serum separating gel) or plasma (lithium heparin, sodium heparin or potassium EDTA) samples.

QUALITY CONTROL
Good Laboratory Practice (GLP) requires the use of quality control specimens in each series of assays in order to check the performance of the assay. Controls should be treated as unknown samples, and the results analysed with appropriate statistical methods.
The kit controls provided in the kit should be tested as unknowns and are intended to assist in assessing the validity of results obtained with each assay plate.
The mean concentration of each control level is documented in the QC report included with each kit. These mean concentration levels are determined over several assays which are run in duplicate in multiple locations across each plate.

LIMITATIONS OF USE
As in the case of any diagnostic procedure, results must be interpreted in conjunction with the patient’s clinical presentation and other information available to the physician.
The performance characteristics of this assay have not been established in a paediatric population.
Heterophilic antibodies in human serum can react with reagent immunoglobulins, interfering with in vitro immunoassays6 . Patients routinely exposed to animals or to animal serum products can be prone to this interference and anomalous values may be observed.