DOCUMENTS leaked from the headquarters of the International Association of Athletics Federations were used on Saturday by German broadcaster ARD/WDR to claim that 146 medals (55 gold) in six World Championships and three Olympics since 2001, have been won by endurance athletes whose blood test results have been deemed "suspicious" by independent international doping experts.

The news, followed up yesterday by the Sunday Times and BBC, has provoked claims that athletics is in the same "diabolical state" as cycling during the Lance Armstrong era.

The newspaper claims that the IAAF attempted initially to block publication of information based on more than 12,000 blood tests from 5000 athletes, many of them icons of the sport. The information has been released by a whistle-blower, and respected analysts suggest competitors have doped with impunity. They accuse the IAAF of doing nothing.

The global athletics authority's legal and anti-doping experts are analysing the reports, and will issue a statement, though probably not before tomorrow. Legal action against both TV and the newspaper is a distinct probability, I understand.

The world body said in a statement that the story was "largely based on analysis of an IAAF data base of private and confidential medical data which has been obtained without consent". Indications are that the IAAF will defend themselves against all the allegations.

The stakes could not be higher. To be tarred with the same brush as the world cycling body, the UCI, would be devastating, not merely in terms of the sport's integrity, but commercially.

The UCI, it was claimed, colluded in turning a blind eye to the doping regime which allowed Armstrong to win seven Tour de France titles of which he was ultimately stripped.

Sponsors could defect from athletics in droves, as they did when whole cycling teams folded. It would devalue TV rights fees right up to the Olympics. Though revelations come too late to impact on fees for the World Athletics Championships in Beijing this month, the controversy will overshadow it if the IAAF cannot satisfactorily explain.

Collateral fall-out would range from sponsorship contracts of innocent athletes to major charities to which the sport is linked. Athletes denied medals might even have grounds to sue the world body. Nike, which had bankrolled Armstrong's cancer charity for nine years, pulled out when the Texan was outed.

To compare the scale of athletics' problems with those of cycling is misleading, however. Illegal doping was revealed to be the norm for road cycling teams. The reality from the leaked athletics data is that while there are grounds for suspicion in the case of 800 of 5000 athletes tested, the inflated readings of so-called "blood scores" do not in themselves confirm doping. The data also means 4200 athletes – the vast majority – are clean.

These, incidentally, include double Olympic champion Mo Farah who for months has been the victim of slurs and innuendo. The data specifically excludes any mention of Farah among the 800 "suspicious" cases. Or multiple Olympic and World champion Usain Bolt, and Olympic heptathlon champion Jessica Ennis-Hill, whom it is claimed lost a world title to a Russian "cheat".

There is good reason for not rushing to judgment before hearing the IAAF's considered response. Naming Olympic and World champions with high "blood scores" who have failed no dope test, is a legal minefield. If the sources are convinced they are correct they should name the cheats. By failing to do so they are as guilty of a cover-up as they claim the IAAF may be.

Blood readings, which exercise physiologist Michael Ashenden described as "grotesque" certainly suggest something untoward. However they do not prove guilt. In the past, high readings have prompted targeted tests to be done. For instance, they provided grounds for suspicion that Russian Yelena Arzhakova was a cheat. She won the 2012 European title, but her biological passport readings proved her to be a cheat, and Scotland's Lynsey Sharp was promoted to gold.

Passports were introduced by the IAAF at significant cost and have resulted in other athletes, many of them Russian, being exposed. The cost of anti-doping accounts for 5 per cent of the governing body's budget.

However, anti-doping is far from infallible. England's Commonwealth 800 metres champion Diane Modahl was branded a cheat back in 1994. In proving her innocence, she bankrupted herself. By then the sport was also bankrupt, fighting her, and she received no compensation. Her urine sample had been badly stored, degraded, and gave a false reading. Anti-doping remained adamant this could not happen.

Can we rely on impartiality? The IAAF's chief medical expert, Prof Arne Ljungqvist, once said he needed no further information on naturally-occuring levels of hormone in athletes. Yet wearing his World Anti-Doping Agency hat, the Swede was offering millions in research grants to discover precisely that.

Ljunqvist was asked this during a case involving Scottish European 200m champion Dougie Walker who tested positive for a low but illegal level of nandrolone. Walker wanted the nandrolone levels of elite athletes to be examined after intensive training rather than have his levels compared with the mass of mainstream humanity.

Research on an epidemiological scale – very large numbers of elite athletes and not just large numbers of ordinary mortals – is required.

Some 40 Kenyans were screened for illegal blood-boosting erythropoietin by the IAAF, but disturbingly, we have never had a full accounting of the results. We do need answers.

Drawing off one's own blood, and retransfusing later, thereby increasing the red-cell capacity to carry oxygen, dates back more than 30 years, and is harder to detect. Erythropoeitin is the chemical alternative, and easier to detect. In reporting deaths of endurance sportsmen, notably in cycling and orienteering, we explained how EPO can make blood "as thick as strawberry jam" as one expert put it, increasing the chances of a stroke.

But an effective course for a would-be cheat would cost perhaps £1000 per month, according to a haematologist. For a subsistence farmer in Kenya, that's three years' wages. Like much more in this rekindled doping saga, the numbers don't add up. Clearly investigation is needed, and I don't discount whistle-blowers. It's how many notorious cheats, including Ben Johnson, Marion Jones and Linford Christie, were outed.

These columns have long urged greater anti-doping transparency – and harsher penalties for the guilty. The IAAF have yet to be proved guilty in covering up or ignoring doping data. Their comments in this case may yet prove a watershed.