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AST to Platelet Ratio with Laboratory Upper Limit

Supply the laboratory AST upper limit and platelets expressed in 10⁹/L.

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Use the result with context

Health results are educational estimates, not a diagnosis or treatment recommendation. A qualified clinician can interpret measurements in the context of your health.

Formula and method

AST 80 IU/L, upper limit 40 IU/L and platelets 200 × 10⁹/L give APRI 1.

APRI = 100 × (AST / AST upper limit) / platelets in 10⁹/L.

Worked example

Enter these known values and leave the other values blank.

AST (IU/L)
80 IU/L
AST upper reference limit (IU/L)
40 IU/L
Platelets (10⁹/L)
200 ⋅10⁹/L
AST to platelet ratio index
1

Assumptions and limitations

  • Supply the laboratory AST upper limit and platelets expressed in 10⁹/L. APRI was evaluated for liver fibrosis assessment, especially chronic hepatitis C. A score is not an individual diagnosis; thresholds vary with population.
  • Arithmetic inverses use independent observations. Clear the unknown control before entering the remaining measurements.
  • This measurement calculation does not determine a diagnosis or treatment.

Common questions

How is this result calculated?

APRI = 100 × (AST / AST upper limit) / platelets in 10⁹/L.

Which measurements and units should I use?

Supply the laboratory AST upper limit and platelets expressed in 10⁹/L. APRI was evaluated for liver fibrosis assessment, especially chronic hepatitis C. A score is not an individual diagnosis; thresholds vary with population.

References

Bookify adds independently reviewed bounds for apri: asp_norm > 0; platelet_count > 0.

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