1. Assay precision of the Beckman Coulter AMH GEN II enzyme linked immunosorbent assay (ELISA) assessed using commercial controls and pooled patient serum Kristina HAMILTON 1, 2, Narelle HADLOW 3, Allison MCCLEMENTS 1, Patricia SYKES 1, Peter ROBERTS 2, Phillip MATSON 1, 2 1 Fertility North, Suite 30, Joondalup Private Hospital, Shenton Avenue, Joondalup, WA 6027 2 School of Medical Sciences, Edith Cowan University, Joondalup, WA 6027 3 Biochemistry Department, Pathwest, Sir Charles Gairdner Hospital, Nedlands, WA 6009

2. Introduction Assay precision can be estimated by analyzing the same samples repeatedly and comparing the results obtained Quality control (QC) material can either be commercially-available, being a cocktail which may have an artificial matrix, or patient sample pools reflecting the nature of patient samples being investigated Four serum pools were used as assay controls in a research project measuring AMH levels in early pregnancy (see oral communication presentation #58)

3. Methods The precision of the Beckman Coulter AMH Gen II ELISA kit was assessed using both commercial QC material and pooled patient serum Within-assay variability was calculated by running 20 replicates of each of the four serum pools (A-D) and determining the mean and CV (%) In addition to the manufacturers controls provided with each assay, serum pools A-D were run in 23 assays and between- assay variability calculated

4. Results – within-assay variability The AMH Gen II assay performed well at concentrations between 13.4pmol/ul and 35.7pmol/ul The mean patient AMH concentration for the research project was 21.4±0.8pmol/ul Poolµ ± semCV (%) A5.4±0.0210.5 B13.4±0.025.6 C35.7±0.065.2 D94.9±0.279.0

5. Results – between-assay variability Higher variation in serum AMH measurements between assays was evident Poolµ ± semCV (%) A4.9±0.215.9 B11.7±0.311.1 C30.5±0.58.0 D92.2±2.111.2

6. Results – Internal QC performance QC1 and QC2 (control 1 and 2) at concentrations of 19.8±0.05 and 58.0±0.1pmol/L gave between-assay CVs of 7.1% and 5.0%

7. Conclusion Assay variability is important to determine possible sources of technical error Patient pool samples allow the generation of a precision profile that reflects the samples being tested Higher inter-assay variability means that serial samples from individual patients should be analysed in one assay to minimise this source of error