The PGP (Prothrombin Time, gamma-GT, Platelet) biological index can be used to identify those patients with Schistosoma mansoni infection who have hepatorenal involvement.
Parameters:
(1) prothrombin time, expressed as the International Normalized Ratio (INR)
(2) gamma glutamyltransferase (gamma GT or GGT) in U/L
(3) platelet count per µL
|
Parameter |
Finding |
Points |
|
prothrombin time, as INR |
< 1.25 |
0 |
|
|
1.25 - 1.41 |
1 |
|
|
1.42 - 1.65 |
2 |
|
|
1.66 - 1.99 |
3 |
|
|
>= 2.00 |
4 |
|
gamma GT |
< 20 U/L |
0 |
|
|
20 - 49 U/L |
1 |
|
|
50 - 99 U/L |
2 |
|
|
100 - 199 U/L |
3 |
|
|
>= 200 U/L |
4 |
|
platelet count per µL |
> 340,000 |
0 |
|
|
280,000 - 340,000 |
1 |
|
|
220,000 - 279,000 |
2 |
|
|
160,000 - 219,000 |
3 |
|
|
100,000 - 159,000 |
4 |
|
|
40,000 - 99,000 |
5 |
|
|
< 40,000 |
6 |
where:
• INR = ((patient PT) / (mean normal PT)) ^ (ISI for thromboplastin)
• The normal range for GGT varies with the method, gender and age of the patient. The normal range for the method used is not given.
PGP index =
= (points for prothrombin time as INR) + (points for gamma-GT) + (points for platelet count)
Interpretation:
• minimum score: 0
• maximum score: 14
• Using "a cutoff of 5" identifies the hepatosplenic form of schistosomiasis (92% sensitive, 100% specific). It is unclear if the cutoff is used as > 5 or >= 5.
Specialty: Infectious Diseases, Gastroenterology, Urology
