XXXX --additional new study techniques suggest a heterogenous group.

@entity1 @entity6582 @entity8 @entity455 @entity1283 @entity377 @entity1307 @entity11998 @entity519 @entity25
25 @entity1 with @entity6582 (absolute increase in red cell mass without conventional criteria of primary @entity11998 or known underlying cause) have been further studied for evidence of primary or secondary @entity11998 . Additional non-conventional criteria used were: platelet distribution width, platelet @entity377 ratio, serum @entity1307 , clinical evidence of @entity455 and erythroid culture variables in serum-free system. All had been used in an earlier study in score form to assist in the diagnosis of primary @entity11998 . These @entity1 were also newly assessed for the presence of @entity519 (supine oximeter values, history suggestive of @entity25 ), for @entity8 and for @entity1283 (impalpable) by ultrasound or computerized tomography. 7 @entity1 had erythroid culture scores suggesting primary @entity11998 but the addition of non-culture criteria did not result in any scores more strongly predictive of primary @entity11998 . Supine oximeter values < 92% suggested hypoxaemia as the mechanism of @entity11998 in 3 @entity1 in whom it had not previously been suspected. Some @entity1283 (impalpable) was demonstrated in 6 @entity1 , only 1 of whom had erythroid culture scores suggesting primary @entity11998 . 12 @entity1 had confirmed, raised @entity1307 levels. We conclude that @entity6582 refers to a heterogenous group of @entity1 . Features of primary or secondary @entity11998 may be demonstrated in some of them by additional new study techniques. The raised @entity1307 values found in half the @entity1 were unexpected.
