Blood biomarkers for bone fracture and cartilage injury

1. A method of determining whether a human individual has sustained a bone fracture comprising obtaining a blood sample from said individual and assaying said blood sample for the presence of transforming growth factor beta receptor III (TGFβrIII), wherein the presence of TGFβrIII in said blood sample indicates that said individual has sustained a bone fracture.

2. The method according to claim 1 , wherein the step of assaying the blood sample for the presence of TGFβrIII comprises contacting the blood sample with a binding partner for TGFβrIII to form a binding complex between the binding partner and TGFβrIII present in the blood sample.

3. The method according to claim 2 , wherein the binding complex formed between the binding partner and TGFβrIII present in the blood sample is detected by a detectable label present on the binding partner.

4. The method according to claim 2 , wherein the binding complex formed between the binding partner and TGFβrIII present in the blood sample is detected by adding an antibody that binds to said binding partner or that binds to said TGFβrIII present in said binding complex and detecting said antibody by a detectable label present on said antibody.

5. The method according to any one of claims 1 - 4 , wherein the binding partner for TGFβrIII is a binding protein or an aptamer that binds TGFβrIII.

6. The method according to claim 5 , wherein said binding protein for TGFβrIII is an antibody that binds TGFβrIII.

7. A method of monitoring the state of a bone fracture in an individual comprising measuring the level of transforming growth factor beta receptor III (TGFβrIII) in a first blood sample obtained from the individual and comparing the level of TGFβrIII in the first blood sample with the level of TGFβrIII measured in a second blood sample, wherein the second blood sample was obtained within two weeks, inclusive, after the first blood sample from the individual, and determining whether the level of TGFβrIII in the second blood sample has increased, decreased, or remained the same relative to the level in the first blood sample.

8. A method for determining the time proximity of an individual from a bone fracture comprising:

(a) obtaining a blood sample from said individual at a first time point,

(b) obtaining at least one additional blood sample from said individual at a later time point,

(c) determining the concentration of transforming growth factor beta receptor III (TGFβrIII) in at least said first blood sample and said at least one additional blood sample,

wherein said first time point and said later time point are within two weeks of each other,

wherein a determination that an increase in TGFβrIII concentration of at least about 20% has occurred between said first time point and said later time point indicates that the individual has suffered a bone fracture within two weeks prior to said later time point,

wherein a determination that a decrease in TGFβrIII concentration of at least about 10% has occurred between said first time point and said later time point indicates that the individual has suffered a bone fracture more than two weeks but less than six weeks prior to said later time point, and

wherein a determination that the concentration of TGFβrIII has neither increased nor decreased more than about 6% between said first time point and said later time point indicates that the individual has not suffered a bone fracture for at least six weeks since the later time point.

9. The method according to claim 8 , wherein said first time point and said later time point are within one week of each other.