Establishment and Evaluation of an Internal Quality Control Method for ESR Relays

Figures & data

Figure 1 Establishment and verification process of ESR relay internal quality control.

Abbreviation: NHC, National Health Commission of the People’s Republic of China.

Table 1 Change in ESR of Samples Stored for 24 h at Different Temperatures

Temperature	Number of Cases	ESR (mm/h)		Z value	P value	Change Rate (%), (M[Q1,Q3])
		0 h (M[Q1,Q3])	24 h (M[Q1,Q3])
4 °C	219	30 (16,47)	29 (15,43)	−1.290	0.197	8.45 (5.56,11.11)
Room temperature	219	30 (16,47)	24 (13,39)	−3.373	0.001	20.00 (15.00,25.00)

Abbreviation: ESR, erythrocyte sedimentation rate.

Figure 2 Comparison with initial ESR for samples stored for 24 h at different temperatures.

Figure 3 ESR relay internal quality control chart from March 2021.

Figure 4 Median ESR for patients from March to July 2021.

Table 2 Comparison of Median ESR Between Months from March to July 2021

Indicator	March	April	May	June	July	A/B Ratio	A: Δ (%)	B: 2×Bias Limit (%)
ESR (mm/h)	14	15	15	15	15	0.52	6.76	13.0

Note: Δ=100×[15 (maximum) −14 (minimum)]/14.8 (average) =6.76; Bias limit= One third of the EQA criterion for ESR according to NCCL =6.5%.

Abbreviation: ESR, erythrocyte sedimentation rate.

Table 3 EQA Results for ESR Obtained from NCCL (mm/h)

Sample No.	EQA Result	Target Value	Bias (%)	Allowable Scope	Allowable Bias (%)
202101	9.0	9.4	–4.26	7.4–11.4	±21.3
202102	21.0	20.7	1.45	16.6–24.8	±19.8
202103	68.0	69.2	–1.73	55.4–83.0	±19.9

Note: Date of determination: April 20, 2021.

Abbreviations: ESR, erythrocyte sedimentation rate; EQA, external quality assessment; NCCL, National Center for Clinical Laboratories.