Decoding Sickle Cell Disorders Using Flow Injection Analysis Mass Spectrometry.

Area of Science:

• Hematology
• Analytical Chemistry
• Biochemistry

Background:

• Traditional methods for distinguishing sickle cell states face challenges with co-migrating variants in compound heterozygous conditions.
• Molecular testing is not universally available, necessitating alternative diagnostic approaches.
• Mass spectrometry (MS) offers a potential solution for complex sickle cell disorder diagnostics.

Purpose of the Study:

• To evaluate MS as a method for differentiating sickle cell trait (SCT) from sickle cell disease (SCD).
• To assess the utility of MS-derived globin ratios for subtyping SCD.
• To explore MS as a cost-effective alternative to molecular testing.

Main Methods:

• Hemoglobin analysis using flow-injection triple quadrupole MS on 154 blood samples.
• Calculation of the β^S/β globin ratio to distinguish SCT from SCD.
• Evaluation of additional globin ratios (α/β, γ/β, δ/α) for SCD subclassification into defined groups.

Main Results:

• The β^S/β ratio achieved 90.3% sensitivity and 98.4% specificity in differentiating SCT from SCD (cut-off 0.71).
• Globin ratios (α/β, γ/β, δ/α, β^S/β) significantly discriminated between SCD Group 1 and Group 3 (p < 0.001).
• The γ/β ratio differentiated Group 1 from Group 2, while the δ/α (%) ratio distinguished Group 2 from Group 3 (p < 0.001).

Conclusions:

• A rapid, cost-effective MS approach can differentiate SCT from SCD.
• Globin ratios (γ/β and δ/α) refine SCD subclassification when used with the β^S/β ratio.
• This MS-based method, potentially combined with capillary electrophoresis, enhances diagnostic resolution and may decrease reliance on molecular testing.