How Anti-Doping Labs Analyse Samples: Inside the Science

A sealed sample kit arrives at a WADA-accredited laboratory. Inside are two small bottles of urine, or a pair of blood tubes, packed with paperwork recording every hand that has touched them since collection. What happens between that moment and a sanction being handed down is one of the most tightly controlled analytical processes in world sport. Understanding this science matters just as much for clean athletes tracking their own blood markers as it does for the authorities chasing the cheats.

The Chain of Custody: From Collection to the Lab

Everything begins at collection. A doping control officer splits a urine sample into an A bottle and a B bottle, seals both with tamper-evident caps, and records the sample code on a form the athlete also signs. Blood follows a similar path, drawn into tubes that are centrifuged and refrigerated before dispatch. From that point, the sample is tracked under strict chain-of-custody rules until it reaches a laboratory accredited by the World Anti-Doping Agency (WADA). For Australian samples, a common destination is the Australian Sports Drug Testing Laboratory (ASDTL) in Sydney.

Why A and B Samples Exist

The A and B split is a legal safeguard as much as a scientific one. The lab tests the A sample first. If an adverse analytical finding emerges, the athlete can request that the B sample be opened and analysed, ideally in the presence of their own representative. If the B sample confirms the A result, the finding stands. If it does not, the case typically collapses. This two-bottle system protects athletes from laboratory error and gives anti-doping bodies a defensible evidentiary trail.

The Role of WADA and Sport Integrity Australia

WADA sets the World Anti-Doping Code, maintains the prohibited list, and accredits laboratories worldwide. In Australia, the national anti-doping organisation was formerly the Australian Sports Anti-Doping Authority (ASADA), now folded into Sport Integrity Australia. Sport Integrity Australia handles testing programs, investigations, whereabouts compliance, and results management for Australian sport, working alongside WADA’s framework.

Initial Screening: Immunoassays and GC-MS

Once a sample is logged into the lab’s system, it enters a screening phase designed to flag anything suspicious quickly. The first pass often uses immunoassays, which rely on antibodies that bind to specific classes of compounds. They are fast and relatively cheap, making them ideal for triaging large volumes of samples.

What Immunoassays Can and Cannot Detect

Immunoassays are effective at catching broad classes of drugs such as anabolic steroids, stimulants, and some narcotics. What they cannot do is tell you exactly which compound is present, or at what concentration. They also struggle with substances that do not provoke a strong antibody response, including many peptides and designer drugs. A positive immunoassay screen is therefore a signal to investigate further, not a final result.

GC-MS and the Rise of LC-MS/MS

Gas chromatography-mass spectrometry (GC-MS) has been a workhorse of anti-doping analysis for decades. The sample is vaporised, separated by gas chromatography, and the resulting molecules are identified by their mass spectra. GC-MS is excellent for volatile, heat-stable compounds like many traditional steroids and stimulants. However, it requires derivatisation for many substances and cannot handle large peptides, which is why liquid chromatography-tandem mass spectrometry (LC-MS/MS) has become the dominant confirmation technique in modern labs.

Confirming with Mass Spectrometry: LC-MS/MS and HRMS

LC-MS/MS separates compounds in liquid phase and then fragments them in a collision cell, measuring the resulting ions with high specificity. High-resolution mass spectrometry (HRMS) goes further, measuring mass-to-charge ratios with enough precision to distinguish between molecules that differ by a fraction of a Dalton. Together, LC-MS/MS and HRMS can detect substances at picogram levels, roughly a trillionth of a gram. That sensitivity matters because microdosing protocols are designed specifically to stay below older detection thresholds.

Detecting Peptides and Proteins

Peptide hormones such as erythropoietin (EPO) and human growth hormone (hGH) present a different challenge. They are large, often present in tiny quantities, and can be structurally identical to endogenous versions. Labs use techniques like immunoaffinity purification coupled to LC-MS/MS, and for hGH, specialised assays that distinguish recombinant isoforms from naturally produced hormone. The athlete biological passport has become an important complement here, because indirect markers of EPO or hGH use can be tracked even when the drug itself has cleared.

The Athlete Biological Passport: Tracking Blood Markers Over Time

For those working in athlete monitoring, the ABP is where anti-doping science and performance science overlap most directly. The haematological module monitors markers including haemoglobin, haematocrit, and the OFF-score, a composite value derived from haemoglobin and reticulocyte percentage. The steroidal module tracks ratios of testosterone and related steroids to flag endogenous doping.

Haematological Module: What Markers Matter

The core haematological markers include:

• Haemoglobin concentration, which reflects the blood’s oxygen-carrying capacity
• Haematocrit, the proportion of blood volume occupied by red cells
• Reticulocyte percentage, which indicates how actively the bone marrow is producing new red cells
• The OFF-score, which combines haemoglobin and reticulocytes into a single index

Altitude training can affect all of these markers and complicate ABP interpretation. When Australian athletes head to altitude camps in places like Flagstaff, Arizona, or Thredbo in the Snowy Mountains, their haemoglobin and haematocrit can rise naturally as the body adapts to lower oxygen availability. That is a legitimate physiological response, not doping, but it looks similar on a single test to blood manipulation. The ABP’s statistical models account for altitude exposure when athletes declare it, which is why accurate training-location records matter.

Steroidal Module and Endogenous Steroids

The steroidal module uses ratios such as testosterone to epitestosterone, along with isotope ratio mass spectrometry, to detect exogenous testosterone and related compounds. Because these hormones occur naturally, the passport approach compares an athlete’s values to their own historical baseline rather than a fixed population threshold. This reduces false positives and makes it harder for microdosers to hide.

Beyond the Lab: Intelligence, Retesting, and Whereabouts

Laboratory analysis is only one part of the anti-doping system. Sport Integrity Australia combines test results with intelligence, whereabouts data, and long-term sample storage to build cases that a single test might miss.

Long-Term Storage and Retesting

Samples can be stored for up to ten years under the World Anti-Doping Code. A sample that passes today’s screen might be retested years later with improved analytical methods. Several high-profile cases have been built this way, particularly around retrospective detection of steroids and blood manipulation.

Whereabouts and Target Testing

Athletes in registered testing pools must file whereabouts information so they can be located for out-of-competition testing. Sport Integrity Australia uses this data, along with intelligence from investigations and whistleblowers, to decide who to test, when, and for what. Target testing is not random; it is risk-based and informed by biological passport trends, competition schedules, and suspicious patterns.

What This Means for Athlete Monitoring and Sports Science

For our team, the anti-doping lab process is not a separate world from athlete monitoring. Both rely on the same blood markers, the same analytical precision, and the same need to interpret data in context. When we track an athlete’s haemoglobin over a season, we are using the same variables the ABP uses. When we plan an altitude camp, we know those values will shift and that we need to document the exposure carefully.

Interpreting Blood Markers in Training

A rise in haemoglobin after altitude training is expected and desirable for performance. But without context, that same rise could look suspicious to an anti-doping panel. This is why we encourage athletes to record altitude exposure, illness, hydration status, and training load alongside their blood data. The more context available, the easier it is to distinguish adaptation from manipulation.

The Limits of Anti-Doping Science

No analytical method is perfect. Detection windows vary by substance, some designer drugs are specifically engineered to evade screening, and biological variation can create ambiguity. The ABP and long-term storage help close those gaps, but they depend on continued investment in mass spectrometry, statistical modelling, and international cooperation.

FAQ

What is the athlete biological passport?

The athlete biological passport is a longitudinal record of an athlete’s biological markers, including haemoglobin, haematocrit, and the OFF-score, used to detect patterns consistent with doping rather than relying on a single test result.

Can altitude training trigger a false anti-doping positive?

Altitude training can raise haemoglobin and haematocrit naturally, which may look similar to blood manipulation on a single test. The ABP’s models account for declared altitude exposure, which is why accurate training-location records are important for athletes at camps.

What is the difference between A and B samples?

The A sample is tested first. If an adverse finding is reported, the athlete can request analysis of the B sample, which serves as a confirmation step and a legal safeguard against laboratory error.

How sensitive are modern anti-doping tests?

Techniques such as LC-MS/MS and HRMS can detect substances at picogram levels, roughly a trillionth of a gram, which is sensitive enough to catch many microdosing protocols.

Who runs anti-doping in Australia?

Sport Integrity Australia is the national anti-doping organisation, working within the World Anti-Doping Code framework set by WADA. The Australian Sports Drug Testing Laboratory (ASDTL) in Sydney is one of the WADA-accredited labs that analyses samples.

Anti-doping laboratories are a cornerstone of fair sport, but their work depends on rigorous chain of custody, evolving mass spectrometry, and the athlete biological passport. For clean Australian athletes and the sports science teams supporting them, understanding this process is not just about avoiding sanctions. It is about recognising how closely performance monitoring and anti-doping science now intersect, and why analytical precision protects everyone who competes honestly.