Amber coloured plasma-Case for illustration.

Introduction: Abnormal colour of plasma is infrequently identified during processing of blood and blood components. Common reasons include haemolysis, medications or diet related. Sometimes, the aetiology is unknown. It is a dilemma for every transfusion specialist encountering this situation. Effort should be made to find the aetiology of discolouration of plasma, so that the blood donor can be suitably advised, and a decision can be made regarding the use of blood products.

Materials And Methods: We encountered two cases of orange coloured (amber coloured) plasma in our regular blood donors. All the common reasons for abnormal plasma discolouration were evaluated, including the donor's medication and diet. Spectrophotometry along with Liquid Chromatography-Mass Spectrometry (LC-MS) in both the positive and negative ion modes with literature search helped in arriving at a conclusion.

Results: Haemolysis was ruled out by estimation of plasma haemoglobin. Spectrophotometric analysis of the coloured plasma samples showed a peak, which was absent in normal coloured plasma. This was further investigated using Liquid Chromatography-Mass Spectrometry (LC-MS) in both the positive and negative ion modes. There was no significant difference between the coloured and normal samples in the positive ion mode. But in the negative ion mode, there was a peak observed at 110.5 and 191 m/z value in the profile of the coloured samples in comparison with the normal sample. Literature review shows the peak was corresponding to the presence of quinic acid residues-a substance found in coffee, and potentially excreted into the plasma of an individual with high coffee consumption.

Conclusion: Reporting unusual causes associated with plasma discolouration is important. Present guidelines forbid issue of abnormal coloured blood and blood components for transfusion. Further such reports are necessary to confirm the safety of recipients receiving such units. This is the first case report to our knowledge of quinic acid discolouring blood products.