Indian Journal of Pathology and Microbiology

LETTER TO EDITOR
Year
: 2012  |  Volume : 55  |  Issue : 2  |  Page : 270--271

Falsely low HbA1c value due to a rare hemoglobin variant (HEMOGLOBIN J-MEERUT) - A family study


Anjali Sharma, Sadhna Marwah, Gurdeep Buxi, Raj Bala Yadav 
 Department of Pathology, Dr. RML Hospital and PGIMER, New Delhi, India

Correspondence Address:
Anjali Sharma
Department of Pathology, Dr. Ram Manohar Lohia Hospital and PGIMER, New Delhi
India




How to cite this article:
Sharma A, Marwah S, Buxi G, Yadav RB. Falsely low HbA1c value due to a rare hemoglobin variant (HEMOGLOBIN J-MEERUT) - A family study.Indian J Pathol Microbiol 2012;55:270-271


How to cite this URL:
Sharma A, Marwah S, Buxi G, Yadav RB. Falsely low HbA1c value due to a rare hemoglobin variant (HEMOGLOBIN J-MEERUT) - A family study. Indian J Pathol Microbiol [serial online] 2012 [cited 2022 Aug 19 ];55:270-271
Available from: https://www.ijpmonline.org/text.asp?2012/55/2/270/97912


Full Text

Sir,

Glycosylated hemoglobin (HbA1c) is routinely used to monitor long term glycemic control in diabetic patients. [1] We report a family of rare and abnormal hemoglobin (Hemoglobin J-Meerut) showing falsely low level of HbA1c, not corresponding to their respective fasting plasma glucose levels.

A 23-year-old pregnant female came for thalassemia screening as a part of routine antenatal check-up. Her hemogram and RBC indices were normal. High Performance Liquid Chromatography (HPLC) variant analysis on beta-thal program showed an unknown hemoglobin peak of 19% between P3 and A0 window at the retention time of 1.90 minutes [Figure 1]. HPLC analysis of her family showed the presence of same abnormal hemoglobin peak in her mother and two younger siblings as seen in the patient herself [Figure 1]. The mean percentage of this abnormal hemoglobin variant in these four family members was 19.025% eluted at a retention time of 1.87-1.90 minutes [Table 1]. A diagnosis of HbJ-Meerut was made by matching the retention time in the catalog provided by BioRad Variant system.{Figure 1}{Table 1}

An attempt was made to find out correlation between glycosylated hemoglobin (HbA1c) and the blood sugar levels in all these four family members of HbJ-Meerut. Being aware of the fact that the patient's mother was a recently and incidentally diagnosed case of diabetes mellitus, her fasting blood sugar levels and HbA1c were performed and correlated. Her fasting blood sugar level obtained was 240 mg/dl corresponding to the value >8-9% of HbA1c. [1] Surprisingly, falsely low value of 6.9% was obtained [Figure 2] which corresponds to an average blood glucose level of approximately 170 mg/dl. [1] Similarly, the remaining three family members with HbJ-Meerut also showed falsely low values of HbA1c as shown in [Table 2]. On follow-up, the family showed persistently falsely low values of HbA1c not corresponding to their respective fasting plasma glucose levels.{Figure 2}{Table 2}

Hemoglobin J is a heterogeneous group of fast moving hemoglobins (FMHs), resulting from substitution of a negatively charged amino acid residue in either α, β, or γ globin chains. [2] Hemoglobin J-Meerut can be differentiated and identified solely on its retention time. [2] Blackwell et al. first reported this Hb variant in two sisters from Meerut in India. [3] Worldwide, very few case reports of this hemoglobin variant (Hb-J Meerut) are available. [2]

Our case is the first family of HbJ-Meerut which has come to our department in the past six years depicting its rarity (1 in approx. 4000 cases). Abnormal hemoglobins which produce no hematological symptoms are rarely detected. [4] Srinivas et al. documented that majority of FMHs of J-family are clinically silent and therefore are detected accidentally during family or antenatal screening as seen our case. [2]

This HbJ-Meerut family showed the characteristic finding of falsely lower levels of HbA1c than expected from their plasma glucose levels. A single case report of a diabetic case with Hemoglobin J-Meerut and low HbA1c levels has been reported in the literature. [4]

As HbA1c is based on Hb, both quantitative and qualitative variations in Hb can affect the HbA1c value. [5] If the Hb substitution causes a net change in charge of the Hb (as with Hb variants S, C, D, and G), or if Hb variants cannot be separated from HbA/HbA1c will produce spuriously increased or decreased results by HPLC. [5] Co-elution of the Hb variant with HbA, with resolution of the glycated Hb variant from HbA1c, may under-estimate the HbA1c results as seen in our case.

Thus, knowledge and awareness of Hb-variants affecting HbA1c measurements is essential in order to avoid mismanagement of diabetic patients.

References

1American Diabetes Association. Standards of medical care for patients with diabetes mellitus. Diabetes care 2003;26 Suppl 1:S33-50.
2Srinivas U, Mahapatra M, Pati HP. Hemoglobin J-Meerut, A fast moving hemoglobin- A study of seven cases from India and a review of literature. Am J Hematol 2007;82:666-7.
3Blackwell RQ, Wong HB, Wang CL, Weng MI, Liu CS. Hemoglobin J Meerut: α120 Ala leads to Glu. Biochim Biophys Acta 1974;351:7-12.
4Yagame M, Jinde K, Suzuki D, Saotome N, Takano H, Tanabe R, et al. A diabetic case with Hemoglobin J-Meerut and low HbA1c levels. Intern Med 1997;36:351-6.
5Little RR, Roberts WL. A review of variant hemoglobins interfering with hemoglobin A1c measurement. J Diabetes Sci Technol 2009;3:446-51.