Absolute height SDS | For ages 0 to p years, refer if SDS < a |
a
| SDS referral level before age p | −2.5 | −1.5, −2, −2.5, −3, −3.5, −4 |
| For ages p to 10 years, refer if SDS < b |
b
| SDS referral level after age p | −2.5 | −1, −1.5, −2, −2.5, −3 |
| |
p
| Age (in years) at which the referral level changes | Unspecified | 1, 2, 3 |
Parental height corrected | For ages q to 10 years, refer if: |
c
| SDS cut off level below which SDS must lie | −1.3 | −1, −1.3, −1.5, −2, −2.5 |
| SDS < c, AND |
d
| Difference between target height SDS and SDS | −1.3 | −1, −1.3, −1.5, −2, −2.5 |
| SDS − THSDS < d |
q
| Age (in years) after which the rule is effective | 0, 3† | 1, 2, 3 |
Deflection | For any pair SDS1 and SDS2 measured at ages X1 and X2 (in years), refer if: | | | | |
| r ⩽ X1 < X2 < 10, AND |
e
| Minimal interval (in years) between X1 and X2 | 1‡ | 1, 2, 3 |
| X2–X1 ⩾ e, AND |
f
| SDS cut off level below which SDS2 must lie | Unspecified | 10, 0, −1, −2, −2.5 |
| SDS2 < f, AND |
g
| Height velocity change in SDS per year | −0.25 | −0.20, −0.25,−0.33, −0.50 |
| (SDS2–SDS1)/(X2−X1) < g |
r
| Age (in years) after which the rule is effective | 0, 3† | 3 |