BQT® Test

BQT® is a screening tool which can be used to predict an individual’s risk of developing osteoporosis. BQT® is a simple test to perform, requiring the requiring the collection of just a nail clipping. BQT®will be marketed as Osentia® in the UK and the Republic of Ireland.

BQT® analyses keratin in nail clippings, which can be used as a surrogate biomarker for collagen, a key indicator of bone strength. The test uses a ‘traffic light’ system to indicate an individual’s risk of fragility fracture, with green indicating no risk, amber indicating a moderate risk and red representing individual’s at high risk.

Individuals with a green result have a very low or no risk of suffering a fragility fracture. It is recommended that they under-go a re-tested within two years.

Individuals categorised as amber should consider increasing their consumption of cheese and milk in their diet, increased weight-bearing exercise and the addition of calcium and vitamin D supplements to their diet.

Individuals whose result is in the red zone should visit their GP for further investigation.

Thus by undergoing the BQT®, consumers are able to identify their risk of osteoporosis early, and access appropriate therapeutic intervention and long-term lifestyle changes. Crescent believes this could significantly reduce the annual incidence of 75,000 hip fractures in the UK, which have a 30% mortality rate within the first year.

The proteins in human nail (keratin) and bone (collagen) require sulphation and disulphide bond (S–S) formation for structural integrity. Disorders in either sulphur metabolism or cystathione beta-synthase can lead to structural abnormalities in these tissues. Raman protein spectra provide a method of non-invasive measurement of the degree of sulphation of structurally related proteins that may be indicative of bone health.

BQT® takes about 4 minutes of laboratory time. A nail clipping is inserted in the Raman spectrometer and a laser beam at 785 nm excites the sample. The instrument then captures a spectrum which is indicative of the content and structure of the sample. Using proprietary algorithms, the sample is classified as normal (green), borderline (amber) or problematic for risk of osteoporosis (red).

Crescent’s co-founder, Dr Mark Towler discovered that the strength and appearance of the nails of osteoporosis patients, improved following a course of medication for the disease. Following further investigations using Raman spectroscopy, Dr Towler was able to confirm that the protein structures of healthy nails are different to those with osteoporosis, suggesting a link between the protein structure in the nail and bone health.

Crescent then conducted a clinical trial using nail samples from the Harvard Nurses’ Health Study, where they were able to analyse the protein content of the nail samples and by following the donor’s medical histories, establish a link between keratin content in the nail and the risk of an individual developing osteoporosis.

Following on from this Crescent conducted their largest to date clinical trial, a collaboration between Crescent and 6 hospitals across the UK and Ireland. Osentia demonstrated, after analysing 617 nail samples, that it had a significantly higher sensitivity than the current gold standard DXA. Combining Osentia with the lifestyle questionnaire FRAX, the outcome was 50% more sensitive than DXA. Further analysis in table 1 below, shows that Osentia has a higher sensitivity at the Humerus (28%), wrist (39%), and hip fracture site (71%) compared to DXA.

These results support a strong clinical basis for the utility of Osentia in assessing bone health and risk of bone fracture and demonstrate that Osentia provides a simple, convenient screening tool for risk fracture as recommended by a number of osteoporosis organisations and academics.

Table 1: Performance of different tests for predicting fragility fracture from FRAN.

Cohort: 617 Patients, 356 non-fracture, 261 fracture.

Fracture Site Number of PatientsSensitivity %DXASensitivity %Osentia
















BQT will be marketed as an over-the-counter test in the UK and the Republic of Ireland under the name Osentia®, sold predominately through pharmacies and also over the internet using a consumer-to-lab business model in Q1 2014.