Fish exposed to this blue dye show a spike in certain white blood cells and a drop in others, which means their immune system is stressed or not working normally.
Scientific Claim
Sub-lethal methylene blue exposure (1/5th LC50) for 28 days is associated with a 116% increase in total leukocyte count (to 15.8 ± 0.7 ×10⁴ cells/mm³) and a shift toward neutrophilia (37.5 ± 1.8%) and lymphocytopenia (58.0 ± 1.8%) in Labeo rohita, suggesting immune system disruption.
Original Statement
“TLC increased by 116% (15.8 ± 0.7 ×10⁴ cells/mm³), accompanied by neutrophilia (37.5 ± 1.8%) and lymphocytopenia (58.0 ± 1.8%)”
Evidence Quality Assessment
Claim Status
overstated
Study Design Support
Design cannot support claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The term 'immunosuppression' implies a causal functional outcome, but the study only measured cell counts, not immune function. Only association can be claimed.
More Accurate Statement
“Sub-lethal methylene blue exposure (1/5th LC50) for 28 days is associated with a 116% increase in total leukocyte count (to 15.8 ± 0.7 ×10⁴ cells/mm³) and a shift toward neutrophilia (37.5 ± 1.8%) and lymphocytopenia (58.0 ± 1.8%) in Labeo rohita, suggesting immune cell profile alterations.”
Evidence from Studies
Supporting (1)
The study found that a low dose of methylene blue made the fish’s white blood cell count spike and changed the types of white blood cells, which means their immune system was stressed or messed up — just like the claim says.