| 1 Logistics |
a) Newborn detection of sickle cell disease is the ‘gold standard’ for management of the disease since it allows prevention and treatment of many early and serious complications.
b) For the Manchester Project, it also serves the purpose of monitoring any decline in frequency of affected births as a result of the Project’s intervention of genotype detection and counselling.
c) Deliveries in Manchester occur in 3 maternity centres, numbers below based on 2005 figure
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| Up to 30% of these may occur in subjects resident outside the parish and so are not eligible for the screening/educational intervention. This proportion will be reduced by including Spaldings HS and Knox HS, both just across the Parish border in Clarendon, within the programme. |
| 2 Implementation |
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a) Diagnosis of sickle cell disease at birth is complicated by the high levels of fetal haemoglobin (HbF) which normally range from 60-80%.
b) The detection of sickle cell disease depends on analysis of the relatively small amounts of beta chain synthesis manifest as presence of HbA, HbS, HbC and other beta chain variants.
c) Samples are collected as dried blood spots in filterpaper (Guthrie cards) since dried blood is stable and easy to handle.
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d) Sample collection was initiated at Mandeville Regional Hospital in late March 2008. The techniques used (see section on Laboratory Techniques) caused problems early in the study and results for the first period of sample collection
(March-June 2008) are likely to be inaccurate and are not presented.
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e) Newborn sample collection at Mandeville Regional Hospital was recommenced in August 2008 with better technology and has been more robust and reliable since the introduction of high performance liquid chromatography (HPLC) in mid November 2008.
f) Newborn screening was commenced at Percy Junor Hospital in Spalding and at the Hargreaves Memorial Hospital in Mandeville on January 1, 2009.
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| 3 Sample collection rates |
| a) Mandeville Regional Hospital |
 |
| b) Percy Junor Hospital (Spalding) |
 |
| c) Hargreaves Memorial Hospital |
 |
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4. Laboratory Methods
Diagnosis in the newborn period is complicated by the high levels of fetal haemoglobin (HbF) normally present at birth. Techniques require the detection of small amounts of beta chains in the presence of these high levels of HbF. This is most readily achieved by high performance liquid chromatography (HPLC). Sample chromatograms are shown below.
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| Normal AA Genotype |
AS genotype
(sickle cell trait)
|
AC genotype
(HbC trait) |
|
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| Probable SS disease |
SC disease |
Probable sickle cell-beta+
thalassaemia (note the greater
amount of HbS compared with HbA) |
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|
HPLC Instrument
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5. Results
Mandeville Regional Hospital |
| Samples |
| Month |
collected |
AA |
AS |
AC |
SS |
SC |
Sβ+thal |
Sβothal |
others |
| Aug-08 |
253 |
226 |
13 |
10 |
1 |
1 |
0 |
0 |
2 |
| Sep-08 |
353 |
300 |
38 |
10 |
1 |
0 |
0 |
0 |
4 |
| Oct-08 |
359 |
322 |
26 |
6 |
2 |
1 |
0 |
0 |
2 |
| Nov-08 |
360 |
312 |
33 |
12 |
2 |
0 |
1 |
0 |
0 |
| Dec-08 |
340 |
308 |
22 |
9 |
1 |
0 |
0 |
0 |
0 |
| Jan-09 |
332 |
282 |
30 |
13 |
3 |
1 |
0 |
1 |
2 |
| Feb-09 |
268 |
225 |
30 |
11 |
0 |
0 |
0 |
0 |
2 |
| Mar-09 |
309 |
257 |
39 |
9 |
1 |
2 |
0 |
0 |
1 |
| Apr-09 |
320 |
272 |
34 |
10 |
1 |
0 |
0 |
0 |
3 |
| May-09 |
287 |
238 |
37 |
12 |
0 |
0 |
0 |
0 |
0 |
| Jun-09 |
270 |
236 |
21 |
10 |
3 |
0 |
0 |
0 |
0 |
| Jul-09 |
287 |
243 |
27 |
14 |
1 |
1 |
0 |
0 |
1 |
| Total |
3738 |
3221 |
350 (9.4) |
126 (3.4) |
16 |
6 |
1 |
1 |
17 |
|
