How to create a table with Crosstab in Postgresql?

Question

I have a table tbexame and I want to create another one from a Crosstab, while studying I did the installation of the extension but I am not able to create a select so as to leave the result as follows:

table Crosstab:

paciente_id, parametro_exame_1, parametro_exame_2, ... ,parametro_exame_x
1, positivo, positivo, ...,parametro_exame_x
2, positivo, positivo, ...,parametro_exame_x
...
x, positivo, positivo, ...,parametro_exame_x

original table:

paciente_id, exame, valor
1, parametro_exame_1, positivo
1, parametro_exame_2, positivo
...
x, parametro_exame_x, positivo

Code of select Crosstab:

SELECT * FROM crosstab(
      'SELECT paciente_id, parametro_exame_1
       FROM   tbexame
       ORDER BY paciente_id ASC'
   ) AS ct (paciente_id character varying, exame TEXT);

Error:

return and sql tuple descriptions are incompatible
SQL state: 42601

Note: We do not know the value of x

Another way I tried was:

SELECT * FROM crosstab(
      'SELECT DISTINCT paciente_id, exame, resultado FROM tbexame ORDER BY paciente_id'
   ) AS ct (paciente_id character varying, exame character varying, resultado character varying);

But the result was an examination column and another result. And I actually wanted each parameter to be a column and the result as an attribute.