Table 1.
Emerging POC technologies for SCD screening
| Technique | Advantages | Disadvantages | Cost per test | Equipment cost | Turnaround time | Sensitivity | Specificity | LOD | Refs. |
|---|---|---|---|---|---|---|---|---|---|
| Paper-based hemoglobin solubility | Simple fabrication, ease of use, uses natural color of blood, no batching. | Failure to distinguish between HbSC and HbAS. Blood clotting interferes with the test. Interpretation of results is susceptible to human error. | $0.7 | $300–500 (for automated detection) | 20 mins | 94.2%a | 97.7%a | NA | 177–180 |
|
| |||||||||
| Lateral flow immunoassay (Sickle SCAN) | Ease of use. Rapid results. Absence of auxiliary equipment. | Complex fabrication. Interpretation of results is susceptible to human error. Hb quantification is not supported. | >$5b | NA | 2 mins | 99%c | 99%c | HbA: 40%; HbS: 1%; HbC: 2% | 181 |
|
| |||||||||
| 98.3–100%d | 92.5–100%d | 1–2% | 182 | ||||||
|
| |||||||||
| Lateral flow immunoassay (HemoTypeSC) | Ease of use. Absence of auxiliary equipment. | Complex fabrication. Interpretation of results is susceptible to human error. Hb quantification is not supported. | $0.25e | NA | 20 mins | 100%f | 100%f | HbA: 2.7%; HbS: 3.3%; HbC: 1.3% | 183 |
|
| |||||||||
| Density-based separation | Simple testing procedure. Rapid results. | Need for bulky centrifuge limits applicability to POC setting. Batching required for centrifuge operation. Inability to distinguish between HbAA and HbAS. Inaccuracies due to high HbF levels, health and treatment conditions, and genetic factors affect RBC density. | $0.5 | $150–1,600 | 10 mins | 90–91%g | 88–97%g | 2.8% (dense cells) | 184 |
|
| |||||||||
| Microengineered Electrophoresis (HemeChip) | Low cost. Ease of use. Robustness. Rapid testing. Results comparable to standard electrophoresis tests. Possible integration with mobile devices. Works on the principles of clinical standard electrophoresis test. | High HbF concentration present in newborns less than 4 weeks of age may affect test results. | $0.9 | ~$500h (for automated detection) | <10 mins | 89–100%i | 82–89%i | HbS: 10%; HbF: 10%; HbA:10%; HbC/A2: 3% | 185 |
a
for the detection of the HbS presence.
b
based on personal communication.
c
for the detection of different Hb genotypes.
d
for the detection of the presence of different Hb types.
e
estimated material cost only.
f
for the differentiation between different Hb phenotypes.
g
for the identification of HbSS and HbSC with two-phase and three-phase AMPS.
h
initial assessment of automated reader cost.
i
for differentiating between adjacent bands corresponding to various Hb types.