And clinicians do not adopt a 'blunderbuss' or 'grape-shot' approach. Appropriate tests are ordered in the light of clinical decisions and differing diagnoses, according to the study led by Dr Joanna Latimer, of the School of Social Science, Cardiff University.
The findings are the result of a one-year, intensive case-study of dysmorphology - a specialty in clinical genetics which involves spotting disorders affecting physical development, before or after birth.
It includes recognising particular patterns of physical features in patients with a range of problems or 'troubles', sometimes including delayed intellectual development.
Patients are mainly babies, children and teenagers or young adults, and genetic services are involved because the majority of these syndromes have a genetic basis.
Dr Latimer said: "While there are an increasing number of laboratory examinations that can be made to investigate possible dysmorphic conditions - including DNA and chromosome testing - it is not the case that these are supplanting clinical expertise. Laboratory tests do not simply outweigh clinical evidence."
She continued: "The relationship between how the patient's condition reveals itself and the underlying DNA or chromosome evidence is not entirely predictable.
"Many syndromes are rare and complex, and the laboratory-based technology is not yet available with which to make their genetic basis visible. What we have found is that other, clinic-based techniques and technologies, such as photographs and family trees, have developed with which to do genetic profiling, and which help in distinguishing genetic conditions from other kinds of problems."
Contact: Becky Gammon
Economic & Social Research Council