Table 2.

Example data, with additional information on calculations

Examples	Value	Units	Calculation/comment
Product
Omnipaque	300	mg I/ml
Product density	1.345	g/ml	Product density at room temperature.
Iohexol density	647	mg/mL
Injected dose
Omnipaque, weight	2.8	g
Omnipaque, volume	2.08	mL	2.8 g/1.345 g/mL
Iohexol, weight	1346.9	mg	2.08 mL × 647 mg/mL
Example patient
Sample time	180	min	3 h × 60 min/h
Concentration	0.100	mg/mL	100 μg/mL
Body weight	13	kg
Body height	90	cm
BSA	0.574	m2	$0.024265\times {\mathsf{\text{height}}}^{0.3964}\times {\mathsf{\text{weight}}}^{0.3964}$ =0.024265 × 900.3964 × 130.5378
GFR1p values (BSA-adjusted)
GFR1p-Fleming	72.9	mL/min/1.73 m2	See Table 1
GFR1p-Ham&Piepz	64.6	mL/min/1.73 m2	See Table 1
GFR1p-Groth&Aasted	61.8	mL/min/1.73 m2	See Table 1
GFR1p-Stake	76.5	mL/min/1.73 m2	See Table 1
GFR1p-Jacobsson	75.7	mL/min/1.73 m2	See Table 1
GFR1p-Jacobsson-mod.	74.9	mL/min/1.73 m2	See Table 1
GFR7p calculations
Measured concentrations at all time points:
Time point	Time (min)	C(t) (mg/mL)	C ∗(t) (mg/mL)
1	10	0.464	0.169
2	30	0.343	0.082
3	120	0.156	–
4	180	0.100	–
5	210	0.084	–
6	240	0.072	–
7	300	0.051	–

Two-compartment model: C(t) = Ae ^−αt + Be ^−βt = fast part + slow part

Regression of ln(C(t)) on t for the slow part (time point 3–7):

(Intercept) ln(B) = − 1.16 ⇒ B = 0.31

(Slope) −β = − 0.0061 ⇒ β = 0.0061

C ^∗(t) is the concentration after removing the slow part of the curve:

C ^∗(t) = C(t) − Be ^−βt = C(t) − 0.31e ^−0.0061t

Regression of ln(C ^∗(t)) on t (time point 1–2):

Intercept: ln(A) = − 1.42 ⇒ A = 0.24

Slope: −α = − 0.036 ⇒ α = 0.036

AUC for fast part: $\frac{A}{\alpha }=\frac{A}{\alpha }=6.7$

AUC for slow part: $\frac{B}{\beta }=\frac{B}{\beta }=51.1$

Total AUC = 51.1 + 6.7 = 57.8

Unadjusted GFR**: $\mathit{Cl}=\frac{I}{\mathit{AUC}}=\frac{I}{\mathit{AUC}}=23.3$

Glomerular filtration rate (GFR) adjusted for body surface area (BSA): Cl _BSA = GFR · 1.73/BSA = 70.3. Note that the final calculations are based on more decimals than are shown in the intermediate calculations