Determination of the total protein and triglyceride content of human breast milk on the Synchron CX7 Delta analyser.
BACKGROUND
Premature babies have improved clinical outcomes when fed breast milk with a relatively high protein content. Since there was no convenient way of measuring the macronutrition of breast milk we used our routine laboratory pyrogallol red dye binding method for cerebrospinal fluid microprotein (MTP) and our routine method for serum triglyceride to determine the total protein and triglyceride content of human breast milk.


METHODS
The total protein contents of whole and defatted breast milk samples, randomly collected from 115 nursing mothers, analysed using a pyrogallol red dye binding assay on a Synchron CX7 Delta analyser were compared with the total protein contents determined by dry combustion analysis. Triglyceride concentrations, determined on the Synchron CX7 Delta analyser were compared with their respective creamatocrits.


RESULTS
Passing and Bablok regression analysis (95% confidence interval) gave the following regression equations: y = 5.98(5.48 to 6.56)x-1.32(-2.02 to -0.73) where y is whole milk MTP (g/L) and x is dry combustion analysis (g/100 g); y = 7.09 (6.54 to 7.78)x-2.44 (-3.46 to -1.67) where y is volume-corrected defatted milk MTP (g/L) and x is dry combustion analysis (g/100 g); y = 7.52 (6.86 to 8.24)x+0.90(-2.42 to 3.37) where y is whole milk triglyceride (mmol/L) and x is creamatocrit (%).


CONCLUSIONS
The Synchron CX7 Delta total protein and triglyceride assays provide practical, rapid and reliable methods for the determination of the macronutrition in human milk.
Lynch
P L M
PL
Clinical Chemistry Laboratory, Altnagelvin Area Hospital, Londonderry BT47 6SB, Northern Ireland. mlynch@alt.n-i.nhs.uk
O'Kane
M J
MJ
O'Donohoe
J
J
McCrea
A
A
Pearse
J
J
Wright
A
A
D001681:Biological Assay / Q000295:instrumentation* / Q000379:methods; D005260:Female; D006801:Humans; D008894:Milk Proteins / Q000032:analysis* / Q000378:metabolism; D008895:Milk, Human / Q000737:chemistry*; D011748:Pyrogallol / Q000031:analogs & derivatives* / Q000032:analysis; D014280:Triglycerides / Q000032:analysis* / Q000378:metabolism
D008894:Milk Proteins; D014280:Triglycerides; D011748:Pyrogallol; C058731:pyrogallol sulfonphthalein