Summary of findings 1. Adult participants ‐ platelet count.

Review question	What is the diagnostic accuracy of platelet count for the diagnosis of oesophageal varices in adults with liver disease or portal vein thrombosis?
Population	Adults with diagnosis of chronic liver disease or portal vein thrombosis. Age ≥ 18 years
Settings	Outpatients and inpatients in secondary/tertiary care setting
Study design	Prospective and retrospective cross‐sectional studies. No case‐control studies were found
Index tests	Platelet count
Reference standards	Upper endoscopy
Target condition	Summary accuracy (95% CI)	No. of participants (studies)	Prevalence, Median (range )	Implications in a hypothetical cohort of 1000 people	Post‐test probability	Quality and comments
Any varices Cut‐off value: around 150,000 /mm3 (range 140,000 to 150,000/mm3)	Sensitivity 0.71 (0.63 to 0.77) Specificity 0.80 (0.69 to 0.88) LR+ 3.6 (2.4 to 5.4) LR‐ 0.37 (0.30 to 0.45)	2054 participants (10)	38% (25% to 79%)	With a prevalence of 38%, 380 out of 1000 people will have varices of any size. Of these 380 people, 110 (29% of 380) people with varices will receive misdiagnosis and will not received appropriate prophylaxis or follow‐up The remaining 620 people will have no varices. 124 people (20% of 620) will receive false diagnosis of varices and will undergo an unnecessary endoscopy	Assuming a pretest probability of 38% Post‐test probabilities: If test positive: 69% If test negative: 18%	Most studies are at high risk of bias No predefinition of cut‐off value of the index test for most studies Median prevalence of any varices is lower than that reported by most guidelines (around 50%) .
High risk varices Cut‐off value: around 150,000 /mm3 (range 140,000 to 160,000/mm3)	Sensitivity 0.80 (0.73 to 0.85) Specificity 0.68 (0.57 to 0.77) LR+ 2.5 (1.8 to 3.3) LR‐ 0.30 (0.23 to 0.39)	1671 participants (7)	20% (6% to 48%)	With a prevalence of 20%, 200 out of 1000 people will have varices at high risk of bleeding. Of these 200 people, 40 (20% of 200) people with high‐risk varices will receive misdiagnosis and will not receive effective prophylaxis The remaining 800 people will not have high‐risk varices. 256 people (32% of 800) will receive false diagnosis of high‐risk varices and will undergo an unnecessary endoscopy	Assuming a pretest probability of 20% Post‐test probabilities: If test positive: 38% If test negative: 7%	Most or all studies at high risk of bias No predefinition of cut‐off value of the index test for most studies