Search

The assessment of anti-mullerian hormone (AMH) pre- and post-gonadotoxic treatment helps define reproductive potential in young female adults facing cancer treatment. Normative childhood AMH levels are not well defined. Our objective was to help establish accurate pediatric reference intervals (RIs) for which AMH can be used to assess AMH in pediatric/adolescent survivors. Healthy female volunteers aged 6-19 years were recruited from the Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) cohort. 300 serum samples were analyzed for AMH using an automated assay. Basic demographics and menstrual cycle data on the subjects were recorded at time of sample collection. Serum AMH distribution and RIs (2.5th and 97.5th percentiles) were established in four age groups. One recommended RI (0.98-7.84 ng/mL) was established for females aged 6-19 years after outlier removal. Females 6-9 years demonstrated significantly lower mean AMH concentration than did females 9-12 years (Mean ± SD: 3.18 ± 1.62 and 4.16 ± 2.55 ng/mL, respectively), who in turn demonstrated significantly higher AMH concentrations than those aged 12-15 years (Mean ± SD: 3.75 ± 1.61 ng/mL). Statistical differences are unlikely to be clinically meaningful. Menstrual status and ethnicity did not significantly impact AMH concentrations (p = 0.787 and p = 0.0965, respectively). This is the largest series of its kind using a contemporary, automated, single-batched AMH assay in a healthy pediatric female cohort. In conjunction with future data points and longitudinal data, the RI established may be a useful adjunct to reproductive health counselling delivered to pediatric cancer patients requiring fertility damaging therapies.

Currently there is no reliable method suitable for routine measurement of serum free testosterone (FT).To develop such a method involving liquid chromatography tandem mass spectrometry (LC-IDMS/MS) that directly detects and quantifies the FT present in serum.Ultrafiltrate testosterone obtained from 0.5 mL of serum was partially purified by liquid/liquid extraction and quantified using an Agilent 1200 Series HPLC system coupled to an API 5000 mass spectrometer equipped with an atmospheric pressure chemical ionization ion source. Using split samples serum free testosterone was compared between direct ultrafiltration (UF) coupled LC-MS/MS, analogue FT immunoassay, free testosterone calculated from mass action equations (cFT) and with equilibrium dialysis (ED) coupled LC-MS/MS.Total imprecision determined over twenty runs was6% at 67 pmol/L and 158 pmol/L FT. The dynamic response was linear up to at least 2500 pmol/L while physical LLOQ (18 % CV) equaled 16 pmol/L. The UF method agreed poorly with analogue immunoassay (correlation coefficient 0.667; bias -81%), somewhat better against cFT when total testosterone was determined by immunoassay (correlation coefficient 0.816, bias 21% ) and still better yet against cFT when total testosterone was determined by LC-MS/MS (correlation coefficient 0.8996, bias 10%). Agreement was closest with ED method (correlation coefficient 0.9779, bias 2.4%).We present a relatively simple UF coupled LC-MS/MS definitive method that measures serum free testosterone. The method is relatively fast, reliable and is suitable for the routine clinical laboratory practice.

Objective To determine using a simplified study design trimester-specific FT4 reference intervals in pregnancy with the Roche Modular immunoassay in routine use. Design and methods Surplus blood from 300 women in each trimester, drawn at documented times in the gestation, and from 40 age-matched nonpregnant women were assayed for FT4, thyroid stimulating hormone (TSH) and antithyroid peroxidase autoantibody (anti-TPO). Results After excluding women positive for anti-TPO and with abnormal TSH, reference intervals were calculated as 12.5–19.1 pmol/L (nonpregnant group), 11–19 pmol/L (first trimester), 9.7–17.5 pmol/L (second trimester) and 8.1–15.3 pmol/L (third trimester). 3rd trimester FT4 was significantly lower than that of the second trimester (p