Challenges in evaluating and changing donor criteria

Dr. Mindy GoldmanTransfusion Medicine ResidentsApril 30, 2008

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Plan

Importance of donor criteria

Current donor screening and deferrals

Factors affecting donor responses

Evolution of donor criteria

Assessment of questionnaire, criteria

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RECIPIENT SAFETY

DONOR CRITERIA

BLOOD AVAILABILITY

DONOR SATISFACTION

DONOR SAFETY

OPERATIONAL EFFICIENCY

PUBLIC PERCEPTION

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Donor screening

Donor vital signs

Donor hemoglobin (Hgb)

Donor assessment questionnaire (DAQ)

– Questions 1-13 self-administered

– Questions 14-29 administered by staff

– 87 items queried

– Identical for 1st time, repeat donors

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Donor deferrals

Hgb 44%

Medical, risk factor, self-administered 31%

Indefinite deferrals 4%

Risk factor, oral questions 3%

Inadequate vein 5%

Medication, vaccination 4%

Malaria risk 9%

~ 15% of donors deferred on clinic

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Indefinite deferrals

4% of deferrals are indefinite

vCJD 35%

Other 26%

Medications, medical conditions

26%

History of malaria 3%

HIV, hepatitis risk 10%

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Indefinite deferral, HIV or hepatitis risk First time donors, 1990-2005

0.00

0.50

1.00

1.50

2.00

2.50

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005Year

Per

man

ent

Def

erra

l Rat

e (%

)

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Prevalence of HCV per 100,000 donations 1990-2005

0

100

200

300

400

Year

Pre

va

len

ce

pe

r 1

00

,00

0 D

on

ati

on

s

0

100

200

300

400

Year

Pre

va

len

ce

pe

r 1

00

,00

0 D

on

ati

on

s

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

First Time ObservedFirst Time PredictedRepeat ObservedRepeat Predicted

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Factors affecting donor responses

Donor characteristics

– Language comprehension

– Memory

– Motivation

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Factors affecting donor responses

Mode of administration

– Self-administration

– Face-to-face interview

– Computer administered

– Privacy

Formulation and order of questions

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Components of response

Comprehension

Retrieval

Judgement

Selecting and reporting answers

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Evolution of donor criteria

Developed over time as new knowledge, threats emerged

Many FDA, Health Canada requirements

Little validation that question formulation elicits appropriate information

Differences across jurisdictions demonstrates not based on scientific data

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Donor selection vs testing

100%

10%

0 1 2 3

Laboratory Test

Uti

lity

of

don

or s

elec

tion

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Methods of assessment of criteria

Impossible to do a randomized, controlled trial

Difficult to isolate the effect of an individual criteria

Difficult to choose appropriate outcome measure

Difficult to prove that there will be “zero risk increase” for recipients or donors with a given change in criteria

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Methods of assessment, donor questionnaire

Surveys of undeclared, reportable risks

Operational outcome measures

– Post-donation information

Cognitive research methods

– Degree of correlation, alternative wording

– Qualitative methods such as focus groups

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Methods of assessment, donor questionnaire

Evaluation of donor recall of items queried

DAQ in various formulations and modes of administration

– Self-administered

– Audiovisual computer-assisted format

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Assessment of changes, recipient safety

Rates of transmission of HIV, hepatitis are too low to measure changes, risk modelling can be done

Perform TD testing in deferred donors

Assess risk factors, TD positive donors

Perform donor surveys to estimate anticipated donor loss/gain

Follow TD marker rates after making a change

Experience in other countries

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Recipient safety criteria

Some successful changes

– Removal of the question about fever and headache in the week before donation for WNV

– Shortening of deferral period from 12 to 6 months

for tattoo, piercing, needle-stick injury

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Recipient safety criteria

Some challenges

– Question and deferral for having sex with someone whose sexual background you don’t know

– Intranasal cocaine use

– Indefinite deferral for men who have sex with men, even once since 1977

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History of deferral criteria, MSM

Implemented in Canada in the mid-1980s

By 1989, listed on the donor health assessment questionnaire

Requirement by FDA, Health Canada, Canadian Standards for Blood and Blood Components

FDA Blood Products Advisory Committee held workshops in 2000 & 2005 to reassess criteria

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History of deferral criteria, MSM

Although FDA has not changed their requirement, AABB and US blood suppliers (ABC, ARC) have supported a change to a 12 month deferral period

Neither AABB, ABC, or ARC has supported removal or modification of the deferral criteria other than a change to a shorter deferral period

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History of deferral criteria, MSM

In Canada, 2001 joint CBS/Héma-Québec Consensus Conference on Optimizing the Donor Process

– Current process extremely safe

– No specific recommendations for changes for the MSM criteria

– Advocated continued reassessment of the value of screening questions, based on evolving data

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Challenges in maintaining the current criteria

Time period “since 1977” is effectively becoming a life-time deferral

Advances have been made in the 2 other components of blood safety; testing and Good Manufacturing Practices

Direct donor loss of individuals deferred by the criteria

Indirect donor loss of individuals not directly affected, but feel criteria is discriminatory

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Challenges in maintaining the current criteria

Perceived misalignment with deferral periods for other risk categories

Potential view of Canadian Blood Services as unnecessarily discriminatory by the public

Changes in social policy have occurred with respect to a group that has been discriminated against in the past

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Challenges in changing the current criteria

Lack of data to support possible approaches

Regulated system with very low measurable risks, Mathematical modelling based on many assumptions

Extremely difficult to perform studies to obtain data

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Challenges in changing the current criteria

Any incremental risk is borne by recipients, who have a right to the safest possible transfusion

Public history of past tragedies of HIV, HCV transmission

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Assessment of changes, donor safety

Analysis of adverse events, current criteria

Adverse effects in autologous donors

Experience in other countries

Increase surveillance after changing criteria

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Donor safety criteria

Some successes

– Acceptance of donors on antihypertensive medications

– Acceptance of donors with celiac disease

– Increase in maximal age of donation for regular donors

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Donor safety criteria

Some challenges

– Hemoglobin deferral criteria for female donors

– Donors pulse rate and regularity

– Donors on insulin

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Conclusions

Donor criteria play an important part in ensuring donor and recipient safety, adequacy of supply

Approximately 15% of donors are deferred on the clinic, 4% of donors are deferred indefinitely

Many factors affect donor responses to screening questions

Evaluation of the donor questionnaire, and criteria to protect recipients or donors is challenging