Krouwer Consulting
 

 

Table of Contents

   
  Preface ix
  Acknowledgements xi
Chapter 1 Introduction 1
 

The Business of Diagnostic Testing

1
 

Quality Has Improved--Yet Physicians Rely More on Test Results

1
 

Lifescan: One Manufacturer's Problem

1
 

University of Washington Medical Center: A Laboratory Problem

2
 

Analysis of the Two Problems

2
 

Why Problems Occur

3
 

Financial Incentives Don't Favor Allocating Resources to Quality

3
 

Industry-supported Studies Favor Low-information-content Reports

4
 

Corporate Culture

4
 

Inertia

4
 

How This Book Can Help

5
Appendix The Role of Assay Error in Decisions to Approve Assays for Use 6
Chapter 2 The Diagnostic Assay Development Landscape and the Role of Consultants 7
 

The Technical Environment

7
 

The Commercial Environment

8
 

The Regulatory and Medical Environment

8
 

The Management Environment

8
 

The Five Stages of Product Development

9
 

The Consultant's Environment--How Consultants Get Their Solutions Implemented

10
 

How Statisticians Are Often Perceived and What They Really Do

10
 

When Management Resists--Techniques Used by Consultants to Implement Solutions

11
 

It's About Control

12
 

The Successful Consulting Cycle

13
 

Technology Transfer--The Benefits of a Learning Organization

13
 

Training as Part of a Learning Organization

14
Chapter 3 Stage I: Researching New Opportunities 17
 

Why Scientists and Engineers Need to Understand Financial Models

17
 

Using Decision-analysis-based Financial Models to Value Opportunities

18
 

Decision-analysis Background and Terms

18
 

Selecting Decision-analysis Software

19
 

Creating the Decision-analysis Team

19
 

Preparing an Influence Diagram

19
 

Techniques to Solicit Unbiased Data

21
 

Performing the Analysis--The Results

22
 

The Base Case

22
 

Sensitivity Analysis

22
 

Distribution Analysis

23
 

Techniques to Improve Decision-analysis Models

24
 

The Use of Options

24
 

Markov Analysis

25
 

Methods to Evaluate the Probability of the Technical Success of Opportunities

27
 

Different States of Knowledge Require Different Strategies

28
 

Results Based on Decision Analysis

28
 

Why Management Always Wants the Product Released Sooner

28
 

Why Quality Ranks Low in Terms of Financial Rewards

30
 

Portfolio Analysis

31
 

A Caveat About Using Decision Analysis

31
Appendix How Expected NPVs Are Calculated 31
Chapter 4 Stage II: Proving Feasibility 33
 

Setting Performance Specifications Using Quantitative Methods

33
 

The Importance of Adequate Performance Specifications

33
 

Adequate and Less-than-adequate Performance Specifications

34
 

Nonexistent Specifications

34
 

Nonquantitative Specifications

35
 

Unrealistic Specifications

35
 

Incorrect Specifications

36
 

Specifications Without an Associated Testing and Analysis Method

36
 

Characteristics of an Adequate Performance Specification

37
 

An Example of a Performance Specification for Blood Gas Analyzer Glucose Imprecision

37
 

How Specifications Change Through the Development Process

37
 

Different Origins of Performance Specifications

37
 

Regulatory

38
 

Medical Need

38
 

Competitive

38
 

How Specifications Are Used Differently by Manufacturers and Customers

39
 

Specific Techniques Used to Set Performance Specifications

40
 

Focus Groups and Surveys

40
 

Conjoint Analysis

41
 

Quality Function Deployment

42
 

Different Approaches to Demonstrating Feasibility

45
 

Beware the Technical Administrator

45
Chapter 5 Stage III: Scheduled Development 49
 

Why Products Are Almost Always Late

49
 

Using Design of Experiments Methods to Build Robust Assays

52
 

Why Many Scientists Do not Use Design of Experiments (DOE) Methods

52
 

Cause-and-effect Diagrams and Process Flow Charts

53
 

Factorial and Response-surface Methods

54
 

Experiment-planning Checklist

56
 

Writing Reports That Convert Data into Information

57
 

The Need for Written Reports

57
 

Tips for Converting Data into Information

57
 

A Suggested Report Format

58
 

Symptoms for Problem Reports

59
 

Using Reliability Growth Management to Build Reliable Systems

59
 

An Overview of Reliability Growth Management

60
 

When "Testing in Quality" Is More Efficient Than "Designing in Quality"

61
 

A Model of Instrument System Service Calls

61
 

Redundancy and Reliability Goals

62
 

FRACAS

62
 

Data Analysis

63
 

Corrective Action

63
 

Measuring Progress

64
 

Results Achieved with Reliability Growth Management

66
Chapter 6 Stage IV: Validation 69
 

Why Many Published Validation Methods Fall Short in Assessing Assay Quality

69
 

Validation Methods Within Companies

69
 

Error Modeling Using Simulation

69
 

A Block Diagram or Flow Chart of the System

70
 

A Cause-and-effect Diagram of Error

70
 

How the Error Model Works

71
 

The Simulation Software

72
 

Total Analytical Error

72
 

Multifactor Protocols

76
 

Introduction

76
 

Multifactor Protocol History

76
 

Understanding Multifactor Protocols

76
 

Use and Interpretation of Multifactor Protocols

79
 

Examples

79
 

Implementation

82
 

Additional Special Studies

82
 

Diagnostic Accuracy

82
 

The Detection Limit

83
 

Specific Interference Studies

83
 

Direct vs. Indirect Methods of Estimation

83
 

Estimation of Outliers

83
 

Outlier Goals

84
 

Estimation of Outlier Rates

85
 

External (Customer) Validation Methods

88
 

Why Manufacturer Trials Held at Customer Sites Often Fail to Detect Problems

88
Chapter 7 Stage V: Commercialization 91
 

How Claims Differ from Internal Specifications

91
 

The Typical Data Claim

91
 

The Guaranteed Performance Claim

92
 

Obtaining and Analyzing Remote Data

93
 

Fault Detection

93
 

Data Collection

93
 

Data Analysis

94
 

The Mean Cumulative Repair Function

94
 

Using Process Capability to Compare Performance Across Assays

96
 

The Difference Between Quality Control and Process Capability

97
 

An Example Set of Assays Compared

97
 

Interpretation

98
 

Using Complaints to Improve Assays

101
  Index 103