| NTD | neural tube defect; nitroblue tetrazolium dye; noise tone difference; 5'-nucleotidase |
|---|---|
| OPD | obstetric prediabetic; optical path difference; otopalatodigital [syndrome]; outpatient department; ... |
| PID | pain intensity difference [score]; pelvic inflammatory disease; photoionization detector; picture im... |
| PLSD | protected least significant difference |
| PPID | peak pain intensity difference [score] |