Lionel Messi's double doping test not unusual - Enrique Gomez Bastida

The director of Spain's anti-doping agency says there was nothing out of the ordinary about the "double testing" of Barcelona's Lionel Messi this week.

Messi was asked to give both blood and urine samples when the testers visited Barca's training ground on Monday morning, and the Argentina captain then appeared to complain via social media about being regularly singled out for attention.

However, Enrique Gomez Bastida, the Spanish government-appointed director of the Agencia Espanola Antidopaje, told AS that nobody should have been surprised about what occurred as all clubs had been briefed on the procedures at the beginning of the season.

"We had a meeting beforehand with all team sports to explain how the doping controls were going to work this season," Gomez Bastida said. "For football we met at the headquarters of La Liga and there were representatives present from all first and second division clubs. We explained the new parameters so there would be no surprises later, so they would know the surprise [out of competition] controls would be part of the routine."

The Spanish testers are following guidelines from the World Anti-Doping Agency (WADA), which recommend that more surprise "out of competition" tests are carried out, as these are more efficient than "in competition" controls.

The usual practice is for five players to be randomly selected for urine tests, with one of these also asked to provide a blood sample, Gomez Bastida said.

"All are subject to a urine test, while one also has a blood test," he said. "In the case of Messi and the Barcelona players, it was totally random. Unless we have some reason to suspect a player, and in this case we did not, it is always like this."

Gomez Bastida said that individual players could be specifically chosen to test should there be some "objective" reason to do so.

"At a certain point, if someone has played and stood out in every game, there could be an objective statistic that would lead to a control being carried out," he said. "That could be, for example, on Messi or Cristiano [Ronaldo]. But we also understand that the stars are more protected than others, and it might be more noticeable when it is a player from a smaller team. There are many variables."

Testers had already visited nearly all of Spain's Primera and Segunda Division clubs since this season began, Gomez Bastida said.

"Of the 42 clubs, we have visited almost all of them, except for five," he said. "At Barca, we have just done this surprise test this year."

AS reported that a total of 233 samples -- 48 blood and 185 urine -- have been taken so far this term but did not give any details of test results.

Speaking ahead of Barcelona's Champions League group game at home to Paris Saint-Germain on Wednesday, coach Luis Enrique had played down any annoyance at the club over Monday's visit.

"The double test is one of the possibilities," he said. "It can seem strange to anyone, although now it is within what can happen normally. We are against doping and it all seems good to us. It is about seeing that we are following the laws."

Spanish clubs and authorities have been criticised in the past for not seriously considering the issue of potential doping in football, especially during the 2013 trial of doctor Eufemiano Fuentes, who claimed he had worked with La Liga clubs in the past.