Various blood tests have been proposed, but they are not specific for decompression sickness, they are of uncertain utility and are not in general use.Decompression sickness should be suspected if any of the symptoms associated with the condition occurs following a drop in pressure, in particular, within 24 hours of diving. In 1995, 95% of all cases reported to Divers Alert Network had shown symptoms within 24 hours. This window can be extended to 36 hours for ascent to altitude and 48 hours for prolonged exposure to altitude following diving. An alternative diagnosis should be suspected if severe symptoms begin more than six hours following decompression without an altitude exposure or if any symptom occurs more than 24 hours after surfacing. The diagnosis is confirmed if the symptoms are relieved by recompression. Although MRI or CT can frequently identify bubbles in DCS, they are not as good at determining the diagnosis as a proper history of the event and description of the symptoms. Test of pressure
There is no gold standard for diagnosis, and DCI experts are rare. Most of the chambers open to treatment of recreational divers and reporting to Divers Alert Network see fewer than 10 cases per year, making it difficult for the attending doctors to develop experience in diagnosis. A method used by commercial diving supervisors when considering whether to recompress as first aid when they have a chamber on site, is known as the test of pressure. The diver is checked for contraindications to recompression, and if none are present, recompressed.
1965: LeMessurier and Hills published a paper on A thermodynamic approach arising from a study on Torres Strait diving techniques which suggests that decompression by conventional models results in bubble formation which is then eliminated by re-dissolving at the decompression stops. 1976 – M.P. Spencer showed that the sensitivity of decompression testing is increased by the use of ultrasonic methods which can detect mobile venous bubbles before symptoms of DCS emerge. 1982: Paul K Weathersby, Louis D Homer and Edward T Flynn introduce survival analysis into the study of decompression sickness. 1983: Orca produced the "EDGE", a personal dive computer, using a microprocessor to calculate nitrogen absorption for twelve tissue compartments. 1984: Albert A Bühlmann released his book "Decompression–Decompression Sickness", which detailed his deterministic model for calculation of decompression schedules. Bt 1989: The advent of dive computers had not been widely acceped, but after the 1989 AAUS Dive computer workshop published a group consensus list of recommendations for the use of dive computers in scientific diving, most opposition to dive computers dissipated, numerous new models were introduced, the technology dramatically improved and dive computers became standard scuba diving equipment. Over time, some of the recommendations became irrelevant as the technology improved. c2000: HydroSpace Engineering developed the HS Explorer, a Trimix computer with optional PO2 monitoring and twin decompression algorithms, Buhlmann, and the first full real time RGBM implementation. 2001: The US Navy approved the use of Cochran NAVY decompression computer with the VVAL 18 Thalmann algorithm for Special Warfare operations.