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.