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J R Soc Med. 2004 June; 97(6): 310.
PMCID: PMC1079513

Diagnostic devices in the undergraduate curriculum

Andreas Demetriades (May 2004 JRSM1) comments on the difficulty educators face in deciding which clinical techniques deserve preservation in an age of imaging technologies. Even Laennec faced opposition from those who saw the stethoscope as a threat to traditional practice. Today a case in point is the diagnosis of varicose veins. Management decisions depend on assessment of valvular incompetence, for which medical students are taught the tap test, the cough test and the Trendelenburg tourniquet test. Yet in practice vascular surgeons use hand-held doppler probes and perform duplex scans as necessary. We reviewed the published work regarding accuracy of these clinical tests.

In 1984 McIrvine et al.2 compared clinical tests for saphenofemoral incompetence with findings at surgery in 105 patients. The simplest and most accurate method was the tourniquet test plus hand-held doppler (sensitivity 0.90, specificity 0.45). More recently, De Palma et al.3 found the sensitivities of clinical tests and hand-held doppler to be about the same (0.48) but the addition of doppler to clinical tests raised the sensitivity and increased positive predictive value to 83%. Singh et al.4 asked surgeons ‘hypothetically’ to commit to one of a selection of management protocols having seen findings at preoperative assessment. Inappropriate surgery would have been performed in 20% of limbs on the basis of clinical examination with a tourniquet and in 13% on the basis of tourniquet examination plus hand-held doppler. Kim et al.,5 using duplex scanning as their gold standard, found that the sensitivities of clinical tests ranged from 0.18 to 0.97 and specificities from 0.20 to 0.92. Hand-held doppler was far superior, with sensitivity 0.97 and specificity 0.73 at the saphenofemoral junction.

On the above evidence, clinical tests alone are of low value in assessment of varicose veins and medical education should embrace hand-held doppler.

References

1. Demetriades A. Laennec's legacy. J R Soc Med 2004;97: 257 [PMC free article] [PubMed]
2. McIrvine AJ, Corbett CR, Aston NO, Sherriff EA, Wiseman PA, Jamieson CW. The demonstration of saphenofemoral incompetence; Doppler ultrasound compared with standard clinical tests. Br J Surg 1984;71: 509-10 [PubMed]
3. De Palma RG, Hart MT, Zanin L, Massarin EH. Physical examination, doppler ultrasound and colour flow duplex scanning: guides to therapy for primary varicose veins. Phlebology 1993;8: 7-11
4. Singh S, Lees A, Donlon M, Harris N, Beard J. Improving the preoperative assessment of varicose veins. Br J Surg 1997;84: 801-2 [PubMed]
5. Kim J, Richards S, Kent PJ. Clinical examination of varicose veins—a validation study. Ann R Coll Surg Engl 2000;82: 171-5 [PMC free article] [PubMed]

Articles from Journal of the Royal Society of Medicine are provided here courtesy of Royal Society of Medicine Press