Autentica a la persona, no la contraseña

// Verify the person at the fingerprint reader
procedure TForm1.VerifyFingerprint;
begin
  sgcBiometric1.SensorPool := spSystem;
  sgcBiometric1.BiometricType := btFingerprint;
  sgcBiometric1.Verify;
end;

// Windows does the matching, your handler gets the answer
procedure TForm1.OnVerify(Sender: TObject;
  const Match: Boolean;
  const Identity: string);
begin
  if Match then
    ShowMessage('Verified: ' + Identity)
  else
    ShowMessage('Not recognized');
end;