Autologous blood injection (ABI) is the injection of a small volume of the patient's own unspun whole blood into or around the clinically relevant portion of a symptomatic tendon, on the rationale that the growth factors carried in blood will provoke a healing response in tissue where repair has stalled. It is the simplest and oldest of the blood-derived orthobiologics, it needs no centrifuge or commercial kit, and it was used widely for tendinopathy at the lateral elbow before platelet-rich plasma (PRP) largely displaced it. In sport and exercise medicine (SEM) its main value now is conceptual: it illustrates the whole orthobiologic proposition in its simplest form, and the evidence around it explains why the field has been so difficult to interpret. This page covers what the procedure involves, what UK guidance says, and how it compares with PRP.
How is autologous blood injection performed?
The procedure is deliberately simple. Two to three millilitres of venous blood are drawn from the patient, usually from the antecubital fossa, and injected without any processing into or around the symptomatic portion of the tendon, most classically the common extensor origin at the lateral epicondyle. Local anaesthetic is commonly infiltrated into the skin and surrounding tissue first, and the injection may be performed under ultrasound guidance, which is described as optional rather than intrinsic to the procedure. Because the blood is unspun, the platelet concentration is simply whatever the patient's blood contains rather than a concentrate, which is the fundamental difference from platelet-rich plasma. Protocols vary; one injection, with or without a later repeat, is commonly described, followed by a period of relative rest and then a return to a progressive loading programme.
A small volume of the patient's own unspun whole blood is drawn and injected into the symptomatic portion of the tendon, often with optional fenestration passes through the lesion.
One detail of technique matters more than it first appears. Autologous blood injection is often combined with fenestration or peppering of the tendon, although this is not universal and UK guidance describes it as something that may be done. In studies using concomitant fenestration, the specific effects of the blood and of the needling cannot be separated. Anyone reading the literature on this treatment needs to hold that in mind, because a trial reporting benefit from autologous blood injection may in fact be reporting the effect of needling the tendon. Aftercare follows the usual pattern for these procedures: soreness for a few days is expected, simple analgesia is sufficient, and the loading programme remains the treatment that changes outcomes. Recognised risks are post-procedure pain or flare, bleeding and bruising, infection, injury to the tendon or surrounding tissue, and a theoretical risk of tendon rupture.
What does UK guidance and the evidence say?
The UK position is clear and is worth learning precisely, because it is the kind of statement examiners like. Current UK guidance on autologous blood injection for tendinopathy concludes that the procedure raises no major safety concerns but that the evidence on efficacy is inadequate in both quantity and quality, so it should be used only with special arrangements for clinical governance, consent and audit or research. In practice that means informing clinical governance leads, ensuring the patient understands the uncertainty about efficacy, particularly in the longer term, making them aware of alternative treatments, providing clear written information, and auditing outcomes. The guidance also encourages further research comparing autologous blood injection, with or without techniques to produce platelet-rich plasma, against established non-surgical treatments, and asks specifically that trials document whether a dry needling technique was used.
Platelet-rich plasma delivers a higher platelet concentration than unspun whole blood, but the limited comparative evidence reviewed by UK guidance did not show a substantial difference in efficacy.
The comparison with platelet-rich plasma is the most examinable point on this page. It is intuitive to assume that concentrating the platelets must work better, since the whole rationale rests on platelet-derived growth factors, and platelet-rich plasma does deliver a considerably higher platelet concentration. On anti-doping, platelet-rich plasma and related procedures are explicitly stated to remain permitted, but autologous whole-blood injection is not named as clearly, and the rules were revised in relation to blood withdrawal, so the exact procedure should be checked with the relevant anti-doping organisation rather than assumed. However, the limited comparative evidence reviewed by UK guidance did not show a substantial difference in efficacy, and injection with either preparation was treated as equivalent for the purposes of its recommendations. That should not be read as definitive contemporary equivalence across all preparations and all tendons, but it does mean the evidence does not support a simple assumption that a higher platelet concentration necessarily produces a better clinical outcome. It fits the wider picture set out in the related material on platelet-rich plasma, where the best placebo-controlled trials have not established benefit over placebo injection. The practical conclusion is that autologous blood injection should be presented as an unproven option requiring special arrangements, not offered as a cheaper route to the same result as platelet-rich plasma, and never in place of a progressive loading programme.
Exam Tips
•Autologous blood injection (ABI) uses the patient's own unspun whole blood, typically two to three millilitres, with no centrifugation and no commercial kit.
•The platelet concentration is simply that of the patient's blood, which is the fundamental difference from platelet-rich plasma (PRP).
•The injection is often combined with fenestration, though this is not universal; where it is used, the effects of the needling and of the blood cannot be separated.
•Current UK guidance concludes that safety raises no major concerns but efficacy evidence is inadequate, so use requires special arrangements for clinical governance, consent and audit or research.
•The limited comparative evidence reviewed by UK guidance did not show a substantial efficacy difference between whole blood and platelet-rich plasma, so a higher platelet concentration cannot be assumed to give a better outcome.
•It is an unproven option to be discussed honestly, never a substitute for a progressive loading programme.