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RCPA-QAP
HP-2016 REVIEW
ANNE GILBERT
ICPMR, WESTMEAD HOSPITAL
WESTMEAD, NSW
AUSTRALIA
RCPA-QAP HP- BACKGROUND
Compulsory surveys for Australian and New Zealand laboratories
performing Haemoglobinopathy testing
(National Accreditation Testing Authority NATA)
Running since 1976
Current committee of 3 –
Anne Gilbert, ICPMR, Westmead Hospital, NSW, Australia
Kerryn Weekes, Monash Medical Centre, Melbourne, Vic, Australia
George Chan, Labplus, Auckland Hospital, New Zealand
RCPA-QAP HP PARTICIPANTS -102
COUNTRY NUMBER OF LABS
AUSTRALIA 34
NEW ZEALAND 8
MALAYSIA 29
HONG KONG 13
SINGAPORE 5
SOUTH AFRICA 6
INDIA 2
PHILLIPINES 1
MACAU 1
FRANCE 1
GERMANY 1
OMAN 1
RCPA-QAP HP- BACKGROUND
4 surveys pa
Freeze dried haemolysate, patient history and blood film (digital)
Evaluate Hb A2, Hb F, Hb variant (if present)
Diagnosis
Assessed on all of these parameters
HP 2016 SURVEY SAMPLES
HP16-03 Heterozygous beta thalassaemia- alpha thal not excluded.
HP16-05 Hb Etobicoke [alpha 84(F5) Ser>Arg].
HP16-08 Hb J-Baltimore [beta 16(A13) Gly>Asp].
HP16-10 Low Hb A2, microcytic
HP16-03 EXPECTED FINDINGS
METHOD EXPECTED RESULT
HPLC (Bio-Rad VII) Elevated Hb A2
Cap EPG (Sebia) Elevated Hb A2
Alk EPG Increased Hb A2 band
HP16-03: Hb A2
METHOD CLASSIFICATION MEDIAN MEAN SD CV Number
Biorad Variant II 4.6 4.6 0.1 2.9 58
Biorad D10 4.9 4.9 0.3 5.0 11
Sebia Capillarys/ Minicap 5.1 5.1 0.1 1.8 28
ALL RESULTS 4.7 4.8 0.3 6.5 106
HP16-03
Chinese have high incidence of both beta thalassaemia and alpha 0 thalassaemia.
For all beta thal patients from an alpha 0 endemic region – SEA, Greece must
mention that alpha thalassaemia cannot be excluded
Cannot presume that reduced globin chain imbalance will normalise indices.
15% (2008) to 22% (2011) to 37% in 2016 indicated that alpha thal can’t be excluded
in beta thal heteroztgotes. Still 63% don’t.
HP16-03
Ma, E.S.K.; Chan, A.Y.Y.; Ha, S.Y.; Chan, G.C.F.; Lau, Y.L.; Chan, L.C.Screening for (--SEA) α-globin gene deletion in β-thalassemia carriers and prevention of hydrops fetalis. Haematologica 2000; 85:991
HP16-05 EXPECTED FINDINGS
METHOD EXPECTED RESULT
HPLC (Bio-Rad VII) Hb variant elutes in the D window
Cap EPG (Sebia) Hb variant separates in the D zone
Alk EPG Hb variant with mobility of Hb S/D
Acid EPG Hb variant does not separate.
HP16-05: Hb A2
METHOD CLASSIFICATION MEDIAN MEAN SD CV Number
Biorad Variant II 1.8 1.8 0.1 7.1 65
Biorad D10 2.0 2.2 0.5 21.6 11
Sebia Capillarys/Minicap 2.0 2.0 0.2 7.9 33
ALL RESULTS 1.1 1.8 0.2 9.0 107
HP16-05 Hb ETOBICOKE (a84(F5)Ser>Arg
Rare variant – participants not expected to identify it.
F helix important in oxygenation/deoxygenation and for stabilisation of the globin chain.
Hb Etibicoke is slightly unstable with increased oxygen affinity.
This is not evident in vivo – probably due to low level of alpha variants.
b mutations at this site result in erythrocytosis and a high oxygen affinity phenotype.
HP16-08 EXPECTED FINDINGS
METHOD EXPECTED RESULT
HPLC (Bio-Rad VII) Hb variant elutes in the P3 window
Cap EPG (Sebia) Hb variant separates in the Z12 zone
Alk EPG Hb variant with mobility of Hb J
Acid EPG Hb variant does not separate.
HP16-08: Hb F
METHOD CLASSIFICATION MEDIAN MEAN SD CV Number
Biorad Variant II 2.3 2.8 0.2 6.4 62
Biorad D10 3.2 3.0 0.8 28.3 11
Sebia Capillarys/Minicap 0 0.1 0.2 161.3 32
ALL RESULTS 2.2 1.7 1.1 64.3 111
Hb J-BALTIMORE [beta 16(A13) Gly>Asp].
Rare variant – participants not expected to identify it.
Interferes with Hb A1c quantitation
Haematologically normal.
HP16-10 EXPECTED FINDINGS
METHOD EXPECTED RESULT
HPLC (Bio-Rad VII) Reduced Hb A2
Cap EPG (Sebia) Reduced Hb A2
HP16-10: Hb A2
METHOD CLASSIFICATION MEDIAN MEAN SD CV Number
Biorad Variant II 1.8 1.8 0.1 5.6 64
Biorad D10 1.9 1.9 0.1 4.7 11
Sebia Capillarys/Minicap 1.7 1.7 0.1 4.7 35
ALL RESULTS 1.8 1.8 0.1 6.2 111
HP16-10 COMMENTS
DD alpha thal + delta thal +/or irondeficiency – code created.
Many participant RRs did not indicate reduced Hb A2
Delta thal common in Italians and Greeks –as is beta thal
Beta thal with co-inherited delta thal may mask Hb A2 elevation.
The committee has suggested that laboratories review their reference ranges , which should be calculated based on normal patient population.
Instruments such as Bio-Rad HPLC and Sebia Capillary Electrophoresis: the lower limit for Hb A2 should not be below 2.0 and the upper limit should be less than 3.5.
Currently, only about 30% participants have reference ranges that fall within these limits, which has significant implications for diagnostic decisions.