challenges in evaluating and changing donor criteria dr. mindy goldman transfusion medicine...
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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