Six Sigma Community Healthcare Project Reduces INR Testing Risks

by Brion Hurley

A 2-year grant from the Agency for Healthcare Research and Quality (AHRQ) was awarded to the Cedar Rapids (Iowa) Healthcare Alliance (CRHA) nonprofit organization, to help establish a Community Anticoagulation Therapy (CAT) management clinic to reduce adverse events.

Employees of Rockwell Collins provided technical assistance on Lean, Six Sigma and quality methods. They began work with community health care providers during the analysis and design phase of clinic development. The design and operation of the anticoagulation clinic was heavily influenced by the Six Sigma analysis results of the current anticoagulation management systems within the community.

A summary of the Six Sigma project is as follows:

Whenever measurements are taken on a patient or health care process, the measurement system must be analyzed in order to verify that it is adequate for the application. A Gage Repeatability and Reproducibility (R&R) study was performed to determine if blood samples taken from a patient on warfarin have the same International Normalized Ratio (INR) results when analyzed in different labs (reproducibility) and when analyzed multiple times in the same lab (repeatability). Results showed a statistically significant difference among labs. The therapeutic range for INR is typically 2.0 to 3.0, yet the data showed a difference in INR of 0.4 among labs on a small sample of 10 warfarin patients, almost 50 percent of the range. Root cause analysis revealed that the normalizing number (mean normal prothrombin time, MNPT) utilized in one of the labs varied greatly from other area labs. The team determined a new qualification process for MNPT to keep results consistent across all the labs.

The team also developed a web-based software program that utilizes Statistical Process Control (SPC), Capability Analysis and numerous quality reports to increase patient quality outcomes. In addition, a list of lean improvements to reduce response time and batching of work was also designed into the new clinic.

The benefits expected from these improvements include reduced dosage changes (causing fewer adverse drug events), shorter response times in communicating results to the patient, better patient access to historical results (online access to their test results, to help them take more accountability for managing their results), and less variation in INR results among the labs (causing fewer dosage changes and more time in range).

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