CDC External Quality Assessment/ Proficiency

Testing: An experience in 43+ countries

Shon Nguyen, B.S, MPH

Viral Load and Early Infant Diagnosis Team

International Laboratory Branch Division of Global HIV/AIDS

CGH/Centers for Disease Control and Prevention

Content Overview

• Quality Assurance

•  Proficiency Testing Program

• CDC PT program for EID

• CDC PT program for HIV-1 VL

Quality Assurance (QA)

Safety Quality Control (QC)

External Quality Assessment (EQA)

Site Visits Re-testing Proficiency Testing (PT)

Record Keeping Other

Quality Assurance Activities

External Quality Assessment Activities

Proficiency Testing

Testing of blinded samples at

regular interval by all participants

Retesting

Random selection of clinical samples collected by testing sites and sent to NRL for verification

Site Visits

A team of supervisors assesses site and provides feedback report for improvement

All Pos and 10% Neg 5 Samples 2 or 3x/yr Supervisory Visit

Prepare samples

Analyze results

Prepare report Evaluate

Report results

Examine samples

www.gov.uk

Provider Participants

Proficiency Testing Process

¨  Provide early warning for systematic problem

¨  Increase confidence in the quality of a laboratory’s performance

¨  As a quality indicator for stakeholders at various levels

¨  Quality evaluation and improvement of the testing process

¨  Demonstrate employee competency

¨  To monitor trends in results

Proficiency Testing Benefits

Sample Type Characteristics for PT Liquid (Serum/plasma) •  Requires cold chain transport

•  Risks of spills •  Expensive •  Biohazard

Dried blood spot (DBS) •  Transported at room temperature •  Inexpensive •  HIV-1 Qual testing for Early Infant

Diagnosis (EID)

Dried tube specimen (DTS)

•  Transported at room temperature •  Inexpensive •  HIV-1 RNA Viral Load testing [polymerase

chain reaction (PCR) based assays]

Proficiency Testing Sample Types

¨  Voluntary programs

¨  Offered free of charge

¨  Laboratories actively performing EID/VL testing

¨  Each laboratory may enroll more than one testing platform

¨  Two or three testing cycles per year

CDC PT Programs for EID AND VL

Countries participating in CDC PT Programs

CDC PT Programs for EID

•  Each PT package consists of •  1 sheet of PT Panel (duplicate set of 5 DBS) •  1 sheet of Positive Control (10 DBS) •  1 sheet of Negative Control (10 DBS) •  Instructions and Process checklist form

EID PT Panel Package

0

10

20

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50

60

0

20

40

60

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100

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180 20

06-2

20

06-3

20

07-1

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07-2

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07-3

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08-1

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08-2

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08-3

20

09-1

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ntrie

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Test Cycle

CADU NHLS CDC Countries

EID PT Participants

  CDC NHLS CADUPT

Event Countries Laboratories Countries Laboratories Countries Laboratories

2013-1 39 130        2013-2 37 134 4 21    2014-1 42 103 4 22    2014-2 43 125 4 22 9 202015-I 32 86 10 42 9 21

0 10 20 30 40 50 60

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2006

-2

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-1

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-3

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-1

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-3

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-1

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-1

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-I N

umbe

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Test Cycle

CADU NHLS CDC Countries

EID PT Participants

Garcia et al – JCM 2014

Improved Performance of Laboratories participated in EID PT Program

CDC PT Programs for VL

•  Each PT package consists of •  Two identical sets of 5 DTS member PT panel •  One tube of 13 mL of PBS •  Instructions and processing checklist form

VL PT Panel Package

¨  Testing results are compared intra-platform ¨  Grading of results is completed if 6 or more results are

reported for a given test platform

¨  Results grading: limits of acceptability = mean +/- 3 SD

¨  Results summary report included both graded and non-graded results

¨  All participants receive results report but not all participants receive a graded result

VL PT Results Analysis

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Countries Participants

Test Cycle

Num

ber

Participants and Countries in CDC VL PT Program

0 10 20 30 40 50 60 70 80 90 100

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Number of participants unreported results Number of participants reported results % of reported participants with a passing score

Test Cycle

Num

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% o

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with

a p

assi

ng s

core

VL PT Participants and Results

Mea

n Pr

ofic

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y Sc

ore

Number of Cycles Participated

R² = 0.23072

0

20

40

60

80

100

0 1 2 3 4 5 6 7 8 9 10

n= 23 28 18 17 12 12 13 10 14 8

n 1 5 10 15

Improve Performance of Laboratories Participated in CDC VL PT

§  Majority of participants score 100%

§  HIV-1 VL PT program using virus stock for DTS provides an excellent quality assurance tool

§  Participants’ Challenges in Meeting Result TAT (30 days) Ø  No reagents Ø  Expired kits Ø  Instrument in need of repair Ø  Long delay in clearing customs

Findings

Ø  Improve results TAT and thereby increase results reporting and grading

Ø  Analysis of PT data to evaluate the HIV programs and provide country guidance

Ø  Website for CDC PT programs (ePT)

Ø  Evaluate DBS for HIV-1 VL PT for POCT

Ø  Transfer PT technology to the field

Future Directions

Field participants Academic Affairs, Research and

Quality Assurance, National Health Laboratory Service (NHLS)

South Africa

Bacteriology and Virology laboratory, University Cheikh Anta

Diop, (CADU) Dakar, Senegal

All PT participants who contributed

their data included in this report

CDC-HQ/ILB John N. Nkengasong, PhD

Guoqing Zhang, PhD Rachel S. Beard, PhD

Karidia Diallo, PhD Katrina Sleeman, PhD

Mackenzie Hurlston, MSPH Stephen Jadczak, BS

Artur Ramos, PhD Joy Chang, PhD

Chunfu Yang, PhD Vedapuri Shanmugam, PhD

Dennis Ellenberger, PhD Carole Moore, MLS

John Nahabedian, BS Debrah Boeras, PhD Albert Garcia, MPH

Shambavi Subarao, PhD Chin-Yin Ou, PhD

Christopher Rasberry, MS

Acknowledgements

THANK YOU

QUESTIONS

3. Dry overnight at room temperature

2. Deliver 100 µL per spot

1. whole blood spiked with known number of 8E5 cells

5. Perform validation according to the assay protocol

4. Store in a bag with desiccants and humidity indicator card

3. Dry overnight at room

temperature

2. Deliver 20 µL into each tube

1. Working solution: add virus stock and green dye to PBS

For validation: Add 1.1 mL of PBS

Vortex 10 sec Perform testing immediately or store at 2-8ºC for 24 hrs

or -15ºC or colder for up to 1 week

DTS Preparation and Validation 4. Cap and

store at 2-8oC or -15oC

or colder

5 DTS specimens

HIV

-1 D

TS

VL

PT

VL2

012-

B1

HIV

-1 D

TS

VL

PT

VL2

012-

B1

HIV

-1 D

TS

VL

PT

VL2

012-

B1

HIV

-1 D

TS

VL

PT

VL2

012-

B1

HIV

-1 D

TS

VL

PT

VL2

012-

B1 PBS

buffer (1x)

One vial of PBS

Open one tube at a time, add 1.1 mL of PBS, Cap tube, vortex 10 sec.

Perform testing immediately or store 2-8oC for 24 hrs or -15oC or

colder for up to one week

DTS Testing