Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Validity of whole blood osmolality measurement in sick neonates

  • 17 Accesses

  • 2 Citations


A comparison of heparinized whole blood with plasma osmolality measurements was performed on 100 sick newborns using a vapor pressure osometer. Aliquots of blood samples which had been collected into 1-ml syringes containing sodium heparin for blood gas analyses were used for osmolality determinations. There was excellent correlation between the two methods (r=0.993). A total of 85 samples agreed within 2.0 units. In 38 samples the results obtained by the two methods were identical. The maximum observed discrepancy, present in only 2 samples, was 4 mosmol. Thus, the measurement of whole blood or plasma osmolality provides comparable information. The simplicity, the small volume of the blood sample required and the rapidity of the method make the determination of whole blood osmolality particularly useful in newborns requiring intensive care.

This is a preview of subscription content, log in to check access.


  1. 1.

    Oh W (1976) Disorders of fluid and electrolytes in newborn infants. Pediatr Clin North Am 23: 601–609

  2. 2.

    Bevan DR (1978) Osmometry. 1. Terminology and principles of measurement. Anaesthesia 33: 794–800

  3. 3.

    Boyd DR, Baker RS (1971) Osmometry: a new bedside aid for the management of surgical patients. Surg Clin North Am 51: 241–250

  4. 4.

    Weisberg HF (1974) Clinical diagnosis by laboratory methods (Todd and Sanford), 15th edn. Saunders, Philadelphia, pp 782–785

  5. 5.

    McSwiney RR (1978) Osmosis and osmometry. In: Williams DL, Nunn RF, Marks V (eds) Scientific foundations of clinical biochemistry, vol. 1. Heinemann, London, pp 388–395

  6. 6.

    Maffly RH (1981) The body fluids: volume composition, and physical chemistry. In: Brenner BM, Rector FC Jr (eds) The kidney, vol. 1, 2nd edn. Saunders, Philadelphia, pp 76–115

  7. 7.

    Norman ME, Assadi FK (1979) A prospective study of acute renal failure in the newborn infant. Pediatrics 63: 475–479

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Assadi, F.K. Validity of whole blood osmolality measurement in sick neonates. Pediatr Nephrol 2, 27–28 (1988).

Download citation

Key words

  • Whole blood osmolality
  • Plasma osmolality
  • Neonates