2.2.3. Control

2.2. Quality system in a urinary iodine laboratory

Figure 2. The 12 elements of quality management outlined by WHO [8].

Following the Quality System (Figure 3), it started with method modification done in 2004 with migration from performing test wholly in test tubes to performing test half-way in test tubes (during sample digestion) and half-way in 96-well microtiter plates (during reagent mixing and absorbance reading). Method validation was done by the Institute for Medical

Figure 3. Flowchart of Quality System in the urinary iodine laboratory at the Institute for Medical Research (IMR),

2.2.1. Method

70 Quality Control in Laboratory

Malaysia.

IQC sample preparation follows the order of %CV ≤ 20% for Low control, ≤15% for Medium control and ≤10% for High control, in obtaining allowable ranges (mean 2SD) from replicates of samples of n ≥ 20. The order of %CV set for the laboratory superseded the % CV set by TUIQP, previous EQA program for urinary iodine which set %CV of 20% for all Low, Medium and High control ranges. Each control level (Low, Medium or High) should be included in the assay with minimum replicate of n = 2. External Quality Assurance (EQA) was done once or twice/year (2006–2009) and is currently being done for three cycles/year (2010-present). Current EQA program provides four concentration levels of samples and requires to be assayed in duplicates in three independent assays (n = 6).
