Know your status. It takes one blood test.
Most people with sickle cell trait feel completely healthy, which is why so many only find out when their child is diagnosed. Knowing early gives families choices.
When two carriers have a child
Each pregnancy has the same odds.
In each pregnancy: a 1 in 4 chance of sickle cell disease, and a 1 in 2 chance of the trait.
Tell your doctor if any of these apply
Most people with sickle cell trait feel healthy and have no symptoms, so a simple blood test is the only way to know.
Knowing your status before you start a family gives you time to talk with your partner and your doctor.
- I’m of African, Caribbean, Middle Eastern, South Asian or Mediterranean descent
- I’m in a serious relationship or planning to get engaged
- I’m planning a family
- Someone in my family has sickle cell trait or disease
- I would like to donate blood
Ask for a hemoglobin electrophoresis
Talk to your family doctor or a walk-in clinic. The test measures the types of hemoglobin in your blood and shows whether you carry one copy of the sickle gene. It’s usually covered by your provincial health plan.
Your results come back as the percentage of each type of hemoglobin. See how to read them.
Ask for a hemoglobin electrophoresis. Physicians can order it with:
- CPT code
- 83021
- CCI code
- 1.EE.60.GK.30
How to read your results
Your report lists each type of hemoglobin in your blood and how much of it there is. Here’s what the common patterns usually mean for adults and older children.
| Result | What the report usually shows | What it usually means |
|---|---|---|
| AAThe usual result | HbA about 95 to 98%, HbA2 about 2 to 3% and HbF under 2%. No HbS or HbC. | No sickle or C gene found. You’re not a sickle cell carrier. |
| ASSickle cell trait | HbA about 60% and HbS usually about 35 to 40%. HbA is always higher than HbS. | You carry one sickle gene. Trait is not a disease, but you can pass the gene on to your children. |
| ACHemoglobin C trait | HbA about 50 to 60% and HbC about 30 to 40%. | You carry one C gene. It isn’t a disease, but a child who gets C from you and S from a partner would have HbSC disease. |
| β traitBeta thalassemia trait | HbA2 about 3.5% or higher, often about 4 to 8%. No HbS. | You carry a beta thalassemia gene. It isn’t a disease, though you may have mild anemia that iron won’t fix. With a partner who has sickle cell trait, a child could have sickle beta thalassemia. |
| SSSickle cell anemia, or sickle beta-zero thalassemia | Mostly HbS (over 80 to 90%), no HbA, and HbF usually under 10% unless you take hydroxyurea. | Sickle cell disease. These two types can look almost the same on this test, so more testing may be needed to tell them apart. |
| SCHbSC disease | Roughly equal amounts of HbS and HbC, about 45 to 50% each, and no HbA. | A form of sickle cell disease. Often milder, but serious complications can still happen. |
| Sβ+Sickle beta-plus thalassemia | Some HbA, often about 10 to 30%, but more HbS than HbA, and HbA2 above 3.5%. | A form of sickle cell disease, often milder. The clue that it isn’t trait: there’s more HbS than HbA. |
- Blood transfusion in the past 3 to 4 months? Donor blood adds HbA, which can make sickle cell disease look like trait. Tell whoever orders your test.
- Taking hydroxyurea? It raises HbF on purpose, so your HbF will be higher than these ranges.
- Alpha thalassemia, which is common, can bring HbS in sickle cell trait down to about 25 to 35%. This test often can’t detect it on its own.
- Newborn screening reports list letters from most to least: FA is the usual result, FAS means a sickle cell carrier and FAC a hemoglobin C carrier, while FS, FSC or FSA point to sickle cell disease and need quick follow-up. A newborn screen is always confirmed with more testing.
Labs report results a little differently, so compare yours with the ranges printed on your report. These are typical patterns, not a diagnosis: go over your results with your doctor, and ask about genetic counselling if you’re planning a family. Sources: NHLBI expert panel report, 2014, MedlinePlus, British Society for Haematology, 2023, NHS Sickle Cell and Thalassaemia Screening Programme, CDC and Mayo Clinic Laboratories.
Screened, and still have questions?
Our guide in the SS Feed covers results, family planning and what to ask next.