Adjusting Quality Control Chart Limits for WBC, RBC, Hb, and PLT Counts to Reduce Daily Control Risks in Hospital Laboratory

Figures & data

Table 1 Descriptive Statistics of CBC Test Items

BN		WBC			RBC			Hb			PLT
		Level 1	Level 2	Level 3	Level 1	Level 2	Level 3	Level 1	Level 2	Level 3	Level 1	Level 2	Level 3
1	n	23	23	23	23	23	23	23	23	23	23	23	23
	Mean	3.06	7.16	16.59	2.32	4.44	5.40	6.09	12.55	17.03	83.78	244.74	556.52
	var	0.005	0.010	0.015	0.001	0.001	0.002	0.004	0.006	0.008	13.178	23.656	104.625
	cv	0.167	0.136	0.088	0.019	0.027	0.029	0.064	0.050	0.046	15.729	9.666	18.800
2	n	69	69	69	69	69	69	69	69	69	69	69	69
	Mean	2.95	6.98	16.35	2.41	4.46	5.42	6.29	12.77	17.33	79.45	245.64	554.23
	var	0.003	0.011	0.036	0.001	0.002	0.002	0.003	0.006	0.008	52.192	21.205	65.063
	cv	0.117	0.151	0.218	0.024	0.038	0.045	0.046	0.045	0.046	65.693	8.633	11.739
3	n	71	72	72	71	72	72	71	72	72	71	72	72
	Mean	2.82	6.79	16.03	2.38	4.50	5.58	5.95	12.07	17.11	85.85	249.57	563.13
	var	0.004	0.011	0.037	0.001	0.002	0.003	0.004	0.006	0.011	16.076	27.319	56.759
	cv	0.134	0.156	0.232	0.029	0.041	0.051	0.066	0.051	0.064	18.726	10.946	10.079
4	n	61	61	61	61	61	61	61	61	61	61	61	61
	Mean	2.93	6.82	16.49	2.43	4.60	5.58	6.17	12.37	17.09	83.30	256.31	584.20
	var	0.003	0.009	0.025	0.001	0.001	0.002	0.005	0.005	0.007	22.345	30.218	70.194
	cv	0.112	0.128	0.149	0.026	0.032	0.028	0.087	0.042	0.040	26.826	11.790	12.015
5	n	70	68	72	70	68	72	70	68	72	70	68	72
	Mean	3.07	6.79	16.71	2.37	4.50	5.45	5.79	12.31	16.63	84.07	243.88	554.26
	var	0.004	0.009	0.027	0.001	0.001	0.002	0.005	0.010	0.012	19.140	20.613	81.211
	cv	0.145	0.134	0.163	0.025	0.030	0.028	0.086	0.080	0.073	22.766	8.452	14.652
6	n	70	67	69	70	67	69	70	67	69	70	67	69
	Mean	2.99	6.77	16.80	2.37	4.42	5.37	5.76	11.89	16.34	86.53	247.40	562.59
	var	0.004	0.014	0.031	0.001	0.002	0.001	0.007	0.016	0.016	16.166	32.547	42.774
	cv	0.139	0.214	0.187	0.028	0.039	0.025	0.114	0.132	0.098	18.683	13.156	7.603
7	n	21	22	21	21	22	21	21	22	21	21	22	21
	Mean	3.02	6.68	16.28	2.37	4.43	5.37	5.83	12.29	16.10	75.76	243.00	562.33
	var	0.007	0.010	0.033	0.001	0.001	0.001	0.003	0.009	0.004	36.790	20.762	46.733
	cv	0.229	0.143	0.202	0.010	0.022	0.022	0.054	0.077	0.028	48.561	8.544	8.311

Abbreviations: BN, batch (Lot) number; n, sample size; mean, average; var, variation; cv, variation coefficient.

Figure 1 Comparison chart of Level-1 PLT count detection value.

Table 2 Levene’s Variant Homogenous Test Analysis of Variance Table

Source of Variation	Sum of Squares	Degree of Freedom	Mean Square	F	P-value
Different lot	471.4	6	78.7	10.1
Error	2944.3	378	7.8

Figure 2 Control chart of the platelet count detected in the low-concentration reagent with a new batch number before and after adjustment.

Figure 3 Control chart of the platelet count detected in the medium-concentration reagent with a new batch number before and after adjustment.

Figure 4 Control chart of the platelet count detected in the high-concentration reagent with a new batch number before and after adjustment.

Table 3 ARLs of Detected Platelet Counts at Different Concentrations and at Controlled and Uncontrolled States

Item	Control Chart	(CS)	(UCS)
			Data Shifts 0.5 Times the SD	Data Shifts 1 Times the SD	Data Shifts 2 Times the SD
Low-concentration Level-1	After EB adjustment	319.84	217.47	86.94	20.33
	Before adjustment	62,238.43	55,045.03	37,690.59	17,450.01
Medium-concentration Level-2	After EB adjustment	307.01	185.12	76.68	13.41
	Before adjustment	1477.46	972.76	284.46	43.65
High-concentration Level-3	After EB adjustment	306.26	196.47	78.95	13.93
	Before adjustment	3479.93	2699.23	550.83	60.84

Abbreviations: SD, standard deviation; CS, controlled state; UCS, uncontrolled state.