Feasibility of a rapid method to evaluate platelet survival time.
The purpose of this study was to evaluate the feasibility of a shorter method of performing platelet kinetic studies with respect to the conventional 8-9-day approach.


METHODS
We studied 41 patients (28 women, 13 men; mean age 52 yr) with primary idiopathic thombocytopenic purpura (ITP) (n = 20), secondary ITP (n = 9), HCV associated thrombocytopenia (n = 9), splenectomy (n = 1) and hairy-cell leukemia (n = 1). The patients were in a steady-state of platelet turnover. Initial platelet counts ranged from 19 to 302 x 10(9)/liter (mean value = 83). Platelet survival times (PST) were measured from the blood radioactivity disappearance curve of 111In-oxine-labeled autologus platelets following the recommendations of the International Committee for Standardization in Haematology: blood samples were taken at 30 min and 2 and 4 hr and thereafter daily for 7 days. PST was calculated by the weighted mean method and ranged from 18 to 219 hr (mean value = 98). PST was also calculated using only the data collected at 2, 48 and 96 hr. If the radioactivity in the blood at 96 hr exceeded 10% of the 2-hr value, the additional point at 168 hr was used.


RESULTS
By using this reduced dataset, we obtained a correlation of r = 0.97 with the PST obtained from the whole dataset. In 24 patients, the difference was between +/- 10 hr and exceeded 1 day in only 4.


CONCLUSIONS
About 94% of the data may be recovered with only three or four blood samples and the duration may be shortened to 4 days in a significant proportion of patients (48% of ITP patients). This approach offers the advantages of increased patient throughput, compliance and reduced examination costs.
Baroli
A
A
Department of Nuclear Medicine, Azienda Ospedaliera Maggiore della Carità, Novara, Italy.
Brambilla
M
M
Antonini
G
G
Ciardi
L
L
Bordin
G
G
Cardani
G
G
Rudoni
M
M
Sacchetti
G
G
Inglese
E
E
D001792:Blood Platelets / Q000502:physiology*; D002470:Cell Survival; D016922:Cellular Senescence; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007205:Indium Radioisotopes; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds; D015125:Oxyquinoline / Q000031:analogs & derivatives*; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000097:blood / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging; D013921:Thrombocytopenia / Q000097:blood / Q000000981:diagnostic imaging*; D013997:Time Factors
D007205:Indium Radioisotopes; D009942:Organometallic Compounds; C032950:indium oxine; D015125:Oxyquinoline