Using the failure mode and effects analysis model to improve parathyroid hormone and adrenocorticotropic hormone testing

Figures & data

Table 1 High-risk failure modes identified and their RPN

Failure	O	S	D	RPN
The courier delayed on the way to the laboratory (after taking the sample)	4.00	6.75	8.38	226.13
Leaving the tube unrefrigerated	6.29	7.75	3.13	152.23
The courier does not arrive in a reasonable time	3.67	6.75	5.75	142.31
Send the sample in the pneumatic system without refrigeration	5.25	7.63	3.25	130.10
Tube labeled with incorrect patient	2.38	9.38	4.63	102.98
There is no one in the endocrine laboratory to receive the sample	4.00	4.50	5.38	96.75
The tubes are left on the blood receiving table
Sample delivered to the wrong laboratory	3.73	6.13	4.00	91.45
The assay kit is expired or wrong kit used	1.57	6.40	6.81	68.47
The test equipment is not working	1.86	7.42	4.94	68.01
Computer system crash	2.50	3.75	6.67	62.50
Courier was not ordered during the blood sampling	2.80	6.25	3.25	56.88
The wrong tube was used	3.50	5.38	2.88	54.09
Results assigned to wrong patient	1.63	7.00	4.25	48.34
Data validation was not performed properly	1.38	8.88	3.63	44.24
Incorrect secondary tube label	1.86	8.15	2.90	43.81
Refrigerator failure	1.86	5.23	3.92	38.04
Hemolytic blood sample – sample taken incorrectly	3.38	2.50	4.00	33.75
Centrifuge was not calibrated/chilled	1.00	5.23	5.35	28.00
Wrong test ordered	1.38	3.75	1.63	8.38

Abbreviations: RPN, risk priority numbers; O, occurrence; S, severity; D, detection.

Table 2 Priority matrix of the four highest failure modes

Severity	Occurrence
	Very frequent – 4	Frequent – 3	Occasional – 2	Uncommon – 1	Rare
	Courier delayed taking the sample to the laboratory after pick up	Tube left unrefrigerated	The courier does not arrive in a reasonable time	Sample sent in the pneumatic system without refrigeration	Tube labeled with incorrect patient
Catastrophic – 4	22.6	15.2	14.2	13.01	9.4
Major – 2	15.2	14.1	12	7.8	8
Moderate – 1	12.3	10.2	7.5	6.8	5.3
Minor	9.1	7.8	7	5.8	4.6

Notes: The four colors reflect priority levels for action: urgent (red); prompt (orange); scheduled (yellow); and monitoring (green). The priority matrix provides graphical evidence of which steps require urgent, corrective action.