Table 2.

Karch–Lasagna algorithm

Question	Definite	Probable	Possible	Conditional
Reasonable time sequence (+2)	Yes	Yes	Yes	Yes
Previous knowledge about the adverse reaction (+2)	Yes	Yes	Yes	No
Adverse reaction improved when the drug was discontinued (+2)	Yes	Yes	Yes/No	Yes/No
Adverse event reappeared when the drug was re-administered (0)	Yes	?	?	?
Another alternative explanation (−1)	No	No	Yes	No
Total score		6

Scoring: Definite: ≥ 8; Probable: 6–7; Possible: 4–5; Conditional: 1–3; Doubtful: 0.

Author to add a footnote tah explains the significnace f the undrlines terms in Table 2