CE Courses
CE for MLS & MLT
CE for Phlebotomists
CE for Histologists
HR Courses
Intro to the Medical Lab
Video CE Courses
All Available Courses
Exam Simulators
Exam Simulator for MLS & MLT
NSH + LabCE Histology Exam Simulator
Phlebotomy Exam Simulator
Case Simulators
RBC Morphology Simulator
White Blood Cell Differential Case Simulator
Advanced WBC Differential Case Simulator
Urinalysis Case Simulator
Body Fluid Case Simulator
Bacteriology Case Simulator
LabCE Quiz Game
Contact & Support
Log In
Log In
What is a Cumulative Summation Limit?
How to Subscribe
MLS & MLT Comprehensive CE Package
Includes 173 CE courses, most popular
$95
Add to cart
Pick Your Courses
Up to 8 CE hours
$50
Add to cart
Individual course
$20
Add to cart
Need multiple seats for your university or lab?
Get a quote
The page below is a sample from the LabCE course
Quality Control
. Access the complete course and earn ASCLS P.A.C.E.-approved continuing education credits by subscribing online.
Learn more about Quality Control (online CE course)
What is a Cumulative Summation Limit?
Like the Westgard Rules, the Cumulative Summation Limit or Rule (CUSUM for short) has different approaches.
The CUSUM type used on the following pages is more sensitive to systematic than random error. Nevertheless, it does provide an easy means to detect impending problems.
CUSUM is calculated on worksheets like the one below.
Basically CUSUM works in the following manner: a decision limit is predetermined (See section E. on the right side of the chart, where CUSUM limit is defined as SD x 2.7), and when the CUSUM of control observations exceed this limit, one must look for error in the testing process.
The right side of the worksheet is used to determine the mean, standard deviation (SD), and CUSUM limit.
X
×