Repeat testing

Assessing the appropriateness of test ordering is a complex process, not least because test ordering decisions are made according to nuances of each patient’s condition.³⁸ Appropriateness of test ordering relates to both overuse and under-use, although most commentary has focused on overuse, occurring when a test has been ordered without a clinical indication or within a time frame that is unlikely to provide additional diagnostic information.^{31 32}

The clinical decision support features that can be included in electronic ordering systems have the potential to reduce the repeat test order rate by notifying clinicians when there is an existing identical test order, for that patient, already recorded within the EMR. Clinicians can then choose not to proceed with the order or, if clinically appropriate, to override the alert and proceed with the order. On the other hand, it is much more difficult for a paper order to be identified as a repeat test and, therefore, clinicians have reduced access to information that could assist them make effective decisions. Reductions in the rate of unnecessary repeat tests can result in reductions in patient phlebotomies and workload in the laboratory.^{40 41}

We compared the rates of repeat EUC testing within one-hour and within 24-hours of the previous test, for electronic and paper test orders. The pattern of data shown in Table 14 shows that the proportion of repeat EUC testing in 2011 that occurred within one hour of the previous EUC test was greater for tests ordered using the paper system than those ordered with the EMR (0.69% and 0.25%, respectively), a significant difference (χ2=40.95, p< .001). While, for tests ordered within 24 hours, there was a lower proportion of repeat tests with paper orders than for electronic orders (11.68% and 34.04%, respectively), also a significant difference (χ2=8534.37, p< .001).

Repeat EUC orders created electronically within 24-hours of the previous EUC order for the same patient triggered a Duplicate Order Alert that had to be acknowledged for the order to be created. The finding that 33.79% (the difference between 34.04% of orders within 24 hours and 0.25% of orders within 1 hour) of electronically-ordered repeat EUC tests occurred between one and 24-hours suggests that ordering clinicians were prepared, in many cases, to proceed with a repeat EUC order despite encountering a Duplicate Order Alert. The relative infrequency of electronically-ordered EUC orders within one hour of the previous order may be a consequence of ordering clinicians’ decisions being influenced by their ability to access data on their computers screens about what EUC tests had been ordered in the very recent past. In addition, while the proportion of repeat EUC tests occurring within one-hour of the previous test decreased with time for electronically-ordered tests (overall: 0.40% in 2009, 0.31% in 2010, and 0.25% in 2011), the pattern was not consistent for EUC tests ordered with the paper system (Overall: 0.63% in 2009, 0.56% in 2010, and 0.69% in 2011).

		Year
Hosp	Time Delay	2008		2009		2010		2011
		EMR	Paper	EMR	Paper	EMR	Paper	EMR	Paper
A	<1 Hr n=		0.77% 86		0.77% 91	0.49% 52	1.58% 28	0.24% 27	1.37% 30
								χ2=53.62, p< .001
	<24 Hrs n=		36.79% 4131		32.53% 3821	32.70% 3489	12.51% 221	32.43% 3574	12.75% 280
								χ2=1829.34, p< .001
	Repeat Tests		11230	0	11746	10669	1767	11022	2196
	Total Tests		17542	0	17254	14729	2894	14945	3474
B	<1 Hr n=		0.30% 4		0.29% 4	0.30% 3	0.00% 0	0.21% 2	1.30% 3
								χ2=too few events
	<24 Hrs n=		39.29% 523		37.84% 518	39.13% 394	16.03% 38	34.74% 3574	12.55% 280
								χ2=186.87, p< .001
	Repeat Tests		1331	0	1369	1007	237	950	231
	Total Tests		1968	0	2019	1303	486	1260	465
C	<1 Hr n=		0.53% 13		0.42% 12	0.29% 8	0.00% 0	0.21% 3	0.26% 1
								χ2=too few events
	<24 Hrs n=		41.52% 1016		41.99% 1190	43.63% 1196	26.49% 89	39.09% 955	16.54% 63
								χ2=620.34, p< .001
	Repeat Tests		2447	0	2834	2741	336	2443	381
	Total Tests		4018	0	4111	3794	611	3306	678
D	<1 Hr n=		0.46% 12	0.28% 7	0.00% 0	0.18% 5	2.52% 4	0.41% 12	0.32% 1
								χ2=too few events
	<24 Hrs n=		31.29% 811	29.91% 752	20.50% 33	30.26% 821	18.87% 30	27.77% 805	11.78% 37
								χ2=326.64, p< .001
	Repeat Tests		2592	2514	161	2713	159	2899	314
	Total Tests		4591	4106	338	4358	306	4648	633
E	<1 Hr n=		0.53% 82	0.49% 68	0.75% 20	0.24% 37	0.29% 10	0.27% 48	0.56% 13
								χ2=5.69,p<.05
	<24 Hrs n=		37.17% 5802	38.92% 5367	11.94% 320	37.29% 5661	19.56% 680	37.40% 6573	9.82% 228
								χ2=3987.71, p< .001
	Repeat Tests		15609	13790	2679	15181	3476	17577	2322
	Total Tests		22911	18256	4445	19640	4954	21984	3698
F	<1 Hr n=		0.50% 63	0.33% 37	0.31% 8	0.26% 28	0.25% 7	0.22% 25	0.25% 6
								χ2=0.16,n.s
	<24 Hrs n=		35.99% 4530	36.13% 4102	8.50% 216	31.90% 3382	7.82% 220	30.91% 3568	11.64% 281
								χ2=1734.58, p< .001
	Repeat Tests		12586	11353	2542	10601	2815	11543	2415
	Total Tests		18949	15207	3888	14474	3946	15322	3267
Overall	<1 Hr n=		0.57% 260	0.40% 112	0.63% 135	0.31% 133	0.56% 49	0.25% 117	0.69% 54
								χ2=40.95, p< .001
	<24 Hrs n=		36.71% 16813	36.96% 10221	28.59% 6098	34.82% 14943	14.54% 1278	34.04% 15805	11.68% 918
								χ2=8534.37, p< .001
	Repeat Tests		45795	27657	21331	42912	8790	46434	7859
	Total Tests		69979	37569	32055	58298	13197	61465	12215

Chi-square (χ²) tests of independence; n.s.: Not Significant
Table 14. A comparison, between hospitals and between years, of the proportion and volume of paper- and electronically-ordered (EMR) and repeat EUC tests (in the clinical chemistry department) whose specimens arrived in the CSR within 1- and 24-hours of the previous EUC test, for the same patient.