Table 1.

Summary of analytical performance of colorimetric methods for serum lithium obtained from IQMH (Canada) and RCPAQAP (Australia) proficiency testing surveys between September 2020 to September 2022

Target Lithium Concentration (mmol/L)	Number of surveys	Number of survey samples included	Range of all-methods’ mean# (mmol/L)	Range of all-methods’ SD# (mmol/L)	Range of all-methods’ CV# (%)
<0.4	2	2	0.29 – 0.35	0.04 – 0.05	12.6 – 14.3
0.4 – 0.8	3	4	0.59 – 0.73	0.04 – 0.05	6.0 – 7.1
0.8 – 1.5	4	4	1.03 – 1.43	0.05 – 0.06	3.6 – 5.0
>1.5	7	11	1.71 – 2.70	0.05 – 0.12	3.1 – 4.5

# All-methods mean, standard deviation (SD) and coefficient of variation (CV) presented are summarized from a total of 7 surveys and 21 samples from the Royal College of Pathologists of Australasia Quality Assurance Programs (RCPAQAP) and Institute of Quality Management in Health Care (IQMH) proficiency testing surveys, and reported from 311 participating clinical laboratories in RCPAQAP and 86 IQMH Proficiency Testing Program. This data represents lithium measurements from eight instrument groups (Abbott Architect/Alinity c, Beckman Coulter AU, Beckman Coulter Unicel D×C, Ortho Vitros, Roche cobas c/lntegra 400, Siemens Advia/Atellica, Siemens Dimension, and Siemens Vista) based on the colorimetric method principle.