HPLC is more sensitive to assess urinary albumin than nephelometry in acute stroke patients

Abstract

Microalbuminuria, the appearance of albumin in the urine, is one the first signs of a disease process in many pathological conditions. However, the definition or identification of "microalbuminuria" may depend on the sensitivity of methods used to measure urinary albumin. In the past, immuno‐nephelometry (NM) was used to routinely detect immunoreactive albumin. However, high‐performance liquid chromatography (HPLC) detects both immunoreactive and non‐immunoreactive albumins. Early recognition of microalbuminuria is important, because recent studies have shown that it is associated with elevated risk of stroke. We hypothesized, that use of HPLC will detect microalbuminuria in more patients with acute stroke than NM. Thus in ischemic stroke patients (n=100) the albumin to creatinine ratio was measured by HPLC and NM to characterize microalbuminuria. We have found that HPLC detected albumin in the urine of 81,8% of stroke patients, whereas NM detected it only in 46,5%. The concentration of urinary albumin detected by HPLC was significantly greater than by nephelometry (HPLC: 203,8±37 NM: 106±27 mg/mmol; p<0,001). In conclusion, HPLC can detect microalbuminuria in more stroke patients and perhaps earlier than NM can. Thus use of HPLC seems to be preferable for screening stroke patient for microalbuminuria.Grants: Hungarian Sci. Res. Funds/OTKA T48376, K71591, F68638; Health Sci. Council/ETT 364/2006, Hungarian Neuroimaging Foundation, AHA F. Aff. 0855910D, USA