How do I Improve Turn Around Time in Clinical Laboratory Using Six Sigma?

by Kay Balbi; Updated September 26, 2017

Improve turnaround time (TAT) in clinical laboratory settings -- for example, how long it takes to process a sample or test and return the results -- using six sigma methods. Six sigma measures quality opportunities and failures and works to eliminate defects based upon data-driven performance-improvement initiatives. The term "defects per million opportunities" or DPMO provides an ideal of 99.9 percent quality. Successful use of six-sigma procedures often requires a major shift in measurement systems and process design.

Step 1

Define the services provided, such as urine analysis or blood analysis, and measure current turn times overall. Ask the customer to define her expectation and analyze the gap. Use the smallest measurement increment available, such as seconds or minutes. For example, the customer wants a turn time of 30 minutes for a hemoglobin blood test, and right now you are yielding 60 minutes. The objective in this case would be to reduce current turn time by 30 minutes.

Step 2

Remove variation first. Define each major step of the process such as customer intake, computer update, sample drawn, sample labeled, sample tested, testing validated, results recorded, customer notified, and customer billed. Visualize entire process by creating a top-level flow chart.

Instruct employees to handle every request with a uniform first-in/first-out process so that when a problem occurs it receives visibility. Focus on flow and do not allow employees to put work aside for clarification as these “exception situations” cause 80 percent of the variation in the outputs.

Concentrate efforts on ensuring a consistent process even if the process isn’t yet yielding the results you need.

Step 3

Measure each sub-step in the process to see how long it takes. In this case, we find we have 5 minutes for customer intake, 20 minutes waiting, 7 minutes for blood draw, 1 minute for labeling, 2 minutes for analysis, and 20 minutes waiting before clerk notifies customer of results. In this case, the waiting or queue time is what is eating up turn time. Adjust process to minimize wait time.

To do this, identify areas that exhibit waste, such as overproduction (making things unnecessarily like copies), delays (waiting), transportation (moving data or equipment), wasted motion (walking, non-value added keystrokes), inventory (mismanaged, not enough, too much) and making defective products (adding work to something already defective).

Develop ways to streamline process and communication flow by re-timing or moving work, consolidating tasks, getting rid of non-valued activities, and adding machines or personnel.

Step 4

Benchmark competitors' laboratories to compare how they handle clinical laboratory services. Investigate opportunities to apply new software, new technologies and methods to improve accuracy and responsiveness.

Make sure measurement systems are consistent between provider and customer. For example, the customer may measure the process up to the point that they receive the results whereas a provider may measure the process up to the point of payment. Examine the real needs of the desire to drive down turn times and address these specific areas each time.

Step 5

Control the process by measuring inputs to make sure steps within the process remain consistent. Investigate anomalies and figure out why problems occur. Be proactive against variation by improving training and hiring methods. If one technician takes longer than another, find out why.

For example, during the blood draw stage, the patient is brought to the room, a tourniquet is wrapped around his arm, the technician takes the needle in one hand and a swab in another. After swabbing the area, the technician penetrates the vein with a needle, and releases the tourniquet and then draws the blood. They take the pre-formatted label and affix it to the blood sample and set it in the test area. Another technician talks incessantly, draws the blood the same way but instead of labeling and putting the blood sample in the test area, they walk the customer out the door, and forget to put the sample in the test area until an hour later. This would be the variation that needs to be eliminated to improve the process.

Step 6

Shift the bell curve slowly and methodically, incrementally. If the goal is to reduce turn times by 50 percent or 30 minutes overall, then work to reduce seconds off each step of the process. Set realistic upper and lower control limits by examining current yields. For example, if the blood draw process takes 7 minutes on average, set the lower limit to 60 seconds and the upper limit to 420 seconds. Any time a blood draw takes longer than the 420 seconds, figure out why and eliminate the problems. Each time a task within the process is perfected to take less time, the overall turn time will be reduced, getting you closer and closer to your goal.


  • The DMAIC or Define, Measure, Analyze, Improve and Control critical thinking model is used for six-sigma process improvements.


  • Working to improve one area of the process may negatively impact another area so be cognizant of changes and their effects to the overall outputs of the process. It doesn't make sense to perfect the end of the process if the upfront part of the process is where time is being wasted.

About the Author

Kay Balbi began freelancing in 2009 and is now a business management consultant teaching Six Sigma/Lean. Her written work appears on various websites, focusing on business, health and family lifestyle concerns. Balbi has worked in the corporate world for over 30 years. She received her Bachelor of Science in marketing and a Master of Business Administration in global management from the University of Phoenix.

Photo Credits

  • Young beautiful doctor in the x-ray laboratory image by Andrejs Pidjass from