Georg Ivanovas From Autism to Humanism - systems theory in medicine
2. The medical paradigm and the anomalies of ‘Normal Medicine’
If we focus our attention on the basic item of medicine, the individual value, we are again caught in logical problems. Two examples:
If someone is tested HIV positive (ELISA and Western-Blot with a specifity of 99,99%), is the person infected? Our normal understanding would say, yes with a 99,99% probability. But this is not the case. Actually we have no idea whether the person is infected or not. The probability depends on many factors, especially whether or not the patient has a risky life concerning AIDS. Out of 10.000 men not belonging to a risk group it can be expected (based on clinical knowledge) that one will have AIDS. This man will be tested positive (99,99 % probability). Of the other 9.999 men not having AIDS also one will be tested positive (false positive rate). So the probability that a person out of a non-risk group tested HIV positive has AIDS is about 50% (if our basic assumption is correct). If in a group of 10.000 homosexual men 150 have AIDS, these 150 will be tested positive (99,99 % probability) and of the remaining 9.850 non-infected men one will be tested positive (false positive). The probability that a man tested HIV positive will not have AIDS is 1 out of 151 that is under 1%. So if a man out of a non-risk group is tested positive the probability of having AIDS is about 50%, for a man out of a high risk group it is over 99%. Two men, two positive results, but totally different probabilities. (Gigerenzer: 163-197).
A 65 year old patient with a history of long and heavy smoking, diabetes, hypertension and hypercholesterinaemia and a 35 year old woman with atypical symptoms of angina with a positive an anamnesis but lacking other risk factors make the same day an exercise ECG that shows a horizontal ST - segment depression. Although the test provides an identical result, the probability of a coronary heart disease is much higher in the first case (Niroomand 2004).
What we see here is the fact that the value of a value does not only depend on a correct measurement. Its meaning depends largely on the circumstance under which the person lives. The value as such is meaningless. It is the typical relation between the frame and the content (chap. 3.6) . It is always the frame which decides on the meaning.
Simultaneously the frame (the reference values) is defined through the distribution of single values. That is, the meaning of a value is determined by the frame it constitutes. This fact, approximately depicted by Escher’s Drawing Hands, is a typical result of the recursive nature of all living.