And the order changeth …. Evolving protocols for TTI testing
Dr. Saranya Narayan M.D. (Micro)
Medical Director
Jeevan Blood Bankwww.jeevan.org
The Road travelled
• 1995 – 2012 (March 31st 2012)
• DONATIONS – 1.1 lakhs
• ISSUES - 1.9 lakhs
• NO reported Post transfusion infection.
Jeevan protocols
• Voluntary, non –remunerative, non-replacement donors.
• Walk-in donors – 30-50% to < 1%
• Kits - CE /FDA and DCI approved kits
• All new kits evaluated and validated before routine use.
• Interpretation - All reactive and half the kit cut off samples excluded
S/C.O RATIO = 0.5 OR >Well OD S/CO Result
D1 0.059 0.136 NEGE1 1.543 3.545 REACTIVEF1 0.031 0.071 NEGG1 0.026 0.06 NEGH1 0.029 0.067 NEGA2 0.024 0.055 NEGB2 0.047 0.108 NEGC2 0.059 0.136 NEGD2 0.024 0.055 NEGE2 0.027 0.062 NEGF2 0.021 0.048 NEGG2 0.028 0.064 NEGH2 0.192 0.441 NEGA3 0.016 0.037 NEGB3 0.045 0.103 NEGC3 0.123 0.283 NEGD3 0.019 0.044 NEGE3 0.025 0.057 NEGF3 0.017 0.039 NEGG3 0.023 0.053 NEGH3 0.022 0.051 NEGA4 0.017 0.039 NEGB4 0.029 0.067 NEGC4 0.026 0.06 NEGD4 0.02 0.046 NEGE4 0.019 0.044 NEGF4 0.027 0.062 NEGG4 0.028 0.064 NEGH4 0.023 0.053 NEGA5 0.024 0.055 NEGB5 0.026 0.06 NEGC5 0.341 0.783 G ZONED5 0.027 0.062 NEGE5 0.023 0.053 NEGF5 0.03 0.069 NEG
Kits usedYEAR HBsAg HCV HIV
1995SPECIFICITY 98%SENSITIVITY 100%
2nd & 3rd gen
HCV Ab SPECIFICITY 99.5 %SENSITIVITY 100 %
2nd & 3rd gen
HIV P24 Ag KIT + HIV 1&2 Ab*
SPECIFICITY 99 %, * 82-98%
SENSITIVITY 100%2nd & 3rd gen
2012 SPECIFICITY ~100%SENSITIVITY 100%
4th generation
HCV Ag + AbSPECIFICITY 99.85 %SENSITIVITY 100 %
4th generation
HIV Ag + Ab SPECIFICITY 98.3 –
99.7%SENSITIVITY 100 %
4th generation
TTI Trend 1995 - 2012
HBsAg Anti-HBc Total
Positive Negative
Reject theunit
Core Ab
Anti-HBc Total
Negative
Perform Anti-HBs
Titre
Ant-HBc Positive
Anti-HBc Negative
andHBsAg Negative
Release the unit
Perform Anti-HBs
TitreRelease the unit
Anti-HBc Total
Positive
Anti-HBs Titre
> 200 mIU/mLRelease the sample
< 200mIU/mlReject the sample
Algorithm for Hepatitis B screening
HBsAg Trend 1995 - 2012
Hepatitis C (Ag and Ab)
Reject theunit
Release the unit
If HCV is Negative
If HCV is Positive
Algorithm for Hepatitis C screening
HCV Trend 1995 - 2012
Reject theunit
Release the unit
HIV Negative
HIV Positive
Repeat with Sample from segment
If Positive If Negative
Confirm with Western Blot
WB Not RequiredReject the
Unit
Algorithm for HIV screening ( Ag + Ab)
HIV Trend 1995 - 2012
Algorithm for Syphilis screening (RPR)
If Negative If Positive
Reject theunit
Release the unit
Repeat the test with Dilutions 1:2,1:4 and 1:8
respectively
Titre 1:8 or >
confirm with STS
If the titre is 1:2 and 1:4
reject the unit
Leptospirosis (1997 March – Aug 2002)
~ 20000 donations DFM CULTURE AP-PCR* IgM Ab
POSITIVE(3.9%)
155 /155( 100 % )
88/155( 57 % )
22/26( 85 % )
19/155( 12 % )
EQUIVOCAL - - - 20/155( 13 % )
NEGATIVE - 67/155( 43 % )
4/26( 15 % )
119/159( 75 % )
* AP PCR - Strains : L. Louisiana - 15, L. Canicola - 6,L.Pomona - 1
HUMAN LEPTOSPIROSIS : GUIDANCE FOR DIAGNOSIS,
SURVEILLANCE AND CONTROL
I L SInternational Leptospirosis Society
2003
Can leptospires be transmitted by blood transfusion ?
It is not known precisely when leptospires appear in the blood after infection. It is possible that, during the incubation period, before the infected person becomes ill, leptospires may circulate in the blood and be transmitted via blood transfusion.
Perhaps, in the future, it will be possible for rapid methods such as PCR to be used to check for leptospires in transfusion blood.
Transmission and Exposure
Enhancing Blood SafetyAGENT Window Period
NATJeevan protocols
ELISAResidual risk
HBV 23.9 days 26 days(HBsAg ULTRA)
1:7.64 lakhs
HCV 3.1 days 7.5 days(Ag + Ab)
< 1 in a million
HIV 5.6 days 7 days(Ag + Ab)
< 1 in a million
First case of HIV from blood transfusion traced to Missouri donorAABB Smart Brief Friday, October 22, 2010 12:00 am
"Even the most sensitive screening technologies currently available cannot identify the presence of HIV infection during the first few days after infection," the report concludes. "Eligibility screening questions, if answered accurately, would have excluded the donor because of his sexual history. It is the responsibility of persons who donate blood to answer screening questionnaires accurately to ensure the safest blood supply possible."
Things we have done
Questionnaire modifications
•History of jaundice.
•Question regular donors who have missed donation.
•Number of hours of sleep the previous night.
•Food eaten prior to donation.
Take Home Message - 1
Cost effective & equally sensitive protocols for TTI screening must be adopted in resource
restricted settings.
Take Home Message - 2
Voluntary Blood donors
Pre-donation screening – stringent.
Investment on creating awareness on VBD should take priority.