Laboratory Medicine
Test Directory / Testosterone
Testosterone
Brown clotted serum, gel barrier
| Test | Testosterone |
|---|---|
| Common Abbreviations | TES |
| Profile | NA |
| Tube type | Brown clotted serum, gel barrier |
| Clinical Indication | Clinical evaluation of serum testosterone, along with LH, assists in evaluation of hypogonadism, testicular failure, hyperprolactinaemia, hypopituitarism, some types of liver and kidney diseases and critical illness. Increased serum testosterone levels in females may be indicative of polycystic ovary syndrome or adrenal hyperplasia, among other conditions. The clinical manifestations of excess testosterone in females include infertility, hirsutism, amenorrhoea, and obesity. |
| Specimen Type | Blood |
| Sample type | Serum |
| Minimum Volume | 0.5mL If requesting more than 10 tests please send an additional brown clotted serum sample. |
| Special Precautions | No special requirements |
| Stability | 5 days at 20 - 25°C, 14 days at 2 - 8°C and 6 months at -20°C |
| Turnaround Time | Inpatient: 48 hours Outpatient/ GP: 48 hours |
| Laboratory | York |
| Reference Interval | Males: 1 - 5 years: <0.42 nmol/L, 6 - 10 years: <0.82 nmol/L, 11 - 15 years: <28.8 nmol/L, 16 - 20 years: 3.55 - 35.08 nmol/L, (Clinical Biochemistry 2010; 43: 1045 1050) 20 - 49 years: 8.64 - 29.0 nmol/L, > or equal to 50 years: 6.68 - 25.7 nmol/L (Quoted by the manufacturer) Female: 1 - 5 years: <0.42 nmol/L, 6 - 10 years: <0.82 nmol/L, 11 - 20 years: <2.72 nmol/L, (Clinical Biochemistry 2010; 43: 1045 1050), 20 - 49 years: < or equal to 1.67 nmol/L > or equal 50 years: < or equal to 1.42 nmol/L (Quoted by the manufacturer) |
| Limitations | Analysis should not be performed on haemolysed, icteric or lipaemic samples. The assay is unaffected by biotin <3600 ng/mL. No interference was observed from rheumatoid factors up to a concentration of 1000 IU/mL. In vitro tests were performed on 16 commonly used pharmaceuticals. Of these, only phenylbutazone at therapeutic doses has been shown to interfere causing increased testosterone levels. A strong reaction with nandrolone was found. Testosterone undecanoate (INN international nonproprietary name, WHO) is metabolised to testosterone after administration. The Elecsys Testosterone II assay does not differentiate between endogenous testosterone and exogenous testosterone resulting from metabolized testosterone under testosterone supplementation therapy. In isolated cases, elevated testosterone levels can be seen in samples from female patients with ESRD. Implausible elevated testosterone values in women should be verified by an extraction method or a validated LCMS/MS tandem method. In rare cases, interference due to extremely high titres of antibodies to analyte specific antibodies, streptavidin or ruthenium can occur. Potential interference may be seen from levonorgestrel (levest combined OCP) or norgestrel. |
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