Screening

Carrier screening before and during pregnancy

In the UK, screening early in pregnancy (before 10 weeks' gestation) is recommended for women at high risk of being sickle cell carriers (either living in a high prevalence area or based on family origin). If a woman is found to be a carrier, screening is offered to the father.[15]​​[28]​​ UK guidelines recommend considering preconception testing (or premarital testing, if appropriate) for sickle cell disease in women from high-risk ethnic groups, although this is not included in the National Screening Programme. If the woman is found to be a carrier, her partner should be offered screening.​[15]​

The American College of Obstetricians and Gynecologists recommends universal haemoglobinopathy testing for those planning pregnancy.[16][17]​ Haemoglobin electrophoresis or molecular genetic testing (e.g., expanded carrier screening that includes sickle cell disease) should be performed when planning pregnancy, or at the initial antenatal visit if there are no previous test results available.[16] If a woman is found to be a carrier, her reproductive partner should be offered screening.[17] Information and counselling should be offered alongside screening.[17][18]

Offering antenatal screening for sickle cell disease at the time of pregnancy confirmation in primary care may modestly increase the proportion of women screened before 10 weeks' gestation.[19]

Newborn screening

In the US, all states practise universal neonatal screening, because this is the only way to ensure that all infants with sickle cell disease will be identified. Worldwide approaches to screening vary. It is not reliable to screen infants based on specific racial or ethnic backgrounds.[20]

In the UK, all newborns are offered screening for sickle cell disease as part of the NHS Sickle Cell and Thalassaemia Screening Programme. For babies newly arriving in the UK (or those who missed newborn screening) testing is offered to up to age 1 year.​[15]​[29]​​​

Blood samples from all newborns can be collected by a heel-prick sample. The screen is usually done by multiple laboratory methods. When an abnormal result is found, the laboratory must have a system in place for rapid communication of positive results to the patient's healthcare provider.

Abnormal screening specimens are usually confirmed using a different technique, such as high-performance liquid chromatography, immunological tests, or DNA-based assays.[1][30]​ Appropriate referral to a specialty sickle cell clinic for education, genetic counselling, and routine follow-up care are essential and should occur as soon as the diagnosis is made.

Primary stroke prevention

Transcranial Doppler (TCD) screening of children with HbSS is recommended for primary stroke prevention, starting at 2 years of age and continued annually if TCD is normal, or every 4 to 6 months if TCD is marginal.[31] Children with abnormal results are tested again within 2 to 4 weeks.[32][33]

Screening for pulmonary hypertension

Sickle cell disease increases the risk of pulmonary hypertension, and pulmonary arterial hypertension can impact pregnancy. The American College of Obstetricians and Gynecologists recommends transthoracic Doppler screening of people with sickle cell disease who are of reproductive age, if they have a persistent history of pulmonary embolism, or signs or symptoms of hypoxia.[16] Screening should ideally occur before pregnancy so that further evaluation, such as right-heart catheterisation, can be performed in advance, and information can be given about the advisability of pregnancy. If already pregnant, screening should be performed early and the resting mean pulmonary arterial pressures estimated, so that abnormal echocardiogram findings can be managed by a multidisciplinary team.[34]

Screening for retinopathy

People with sickle cell disease are at risk for retinal disease; screening for retinopathy with a dilated eye examination begins at age 10 years.[35]

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