Evaluation of calculated low-density lipoprotein against a direct assay.

OBJECTIVES: To evalate compare the calculated LDL determined by the Friedewald formula when Tg < 200 mg/dL, 200-399 mg/dL, and > or =400 mg/dL against a direct method. MATERIAL AND METHOD: Samples from 202 participants (122 males, 80 females, aged 20-87 years old) were determined for cholesterol, triglyceride (Tg), high-density lipoprotein (HDL), and low-density lipoprotein (LDL) at Department of Laboratory Medicine, King Chulalongkorn Memorial Hospital (KCMH). LDL was determined by Friedewald formula and a direct method. RESULTS: Intra-assay and inter-assay precisions at Tg <200 mg/dL, 200-399 mg/dL, > or =400 mg/dL of calculated LDL and direct LDL were 4.80%, 3.29%, 20.37%, 4.86, 8.42%, 8.32%, 2.11%, 1.79%, 3.99%, 2.36%, 2.41% and 6.16%, respectively. The mean absolute biases calculated for calculated LDL against direct LDL at Tg <200 mg/dL, 200-399 mg/dL, > or =400 mg/dL and for total samples were 4.70%, 11.73%, 63.65%, and 7.46%, respectively. Linear regression analysis for calculated LDL vs direct LDL for total samples and grouped as Tg <200 mg/dL, 200-399 mg/dL, and > or =400 mg/dL were 0.9190, 0.9796, 0.9440, and 0.7910, respectively. Intraclass correlation coefficient (ICC) at 95% confidence interval of calculated LDL against direct LDL at Tg <200 mg/dL, 200-399 mg/dL, > or =400 mg/dL and for total samples were 0.963, 0.930, 0.767, and 0.889, respectively. CONCLUSION: The present data suggested that direct LDL is superior over calculated LDL in terms of precision and accuracy. The present study supported that at Tg > or =400 mg/dL calculated LDL should not be used and the traditional cutoff of Tg <400 mg/dL for using Friedewald formula should be revised. In addition, regarding patient convenience, financial reason, and precision and accuracy of analytical method, direct LDL is recommended when Tg > or =200 mg/dL.

Determination of reference intervals of HbA1C (DCCT/NGSP) and HbA1C (IFCC) in adults.

OBJECTIVE: To establish HbA1C reference intervals according to DCCT/NGSP (HbA1C DCCT/NGSP) and IFCC (HbA1C IFCC) in adults. STUDY DESIGN: The study was a descriptive study. MATERIAL AND METHOD: The study was done in 144 subjects, with 99 males and 45 females, aged between 19 to 78 years old. All subjects had normal vital signs, physical examination, chest X-ray. Subjects who had hyperglycemia, renal problem, liver problem, anemia, and/or hemoglobinopathy were excluded from the present study. RESULTS: Reference intervals of HbA1C (DCCT/NGSP) is 5.47% (4.79-6.15) and HbA1C (IFCC) is 3.66% (2.88-4.44). The authors also found very high correlation between HbA1C (DCCT/NGSP) and HbA1C (IFCC) of total, male, female, < 35 years old, and > or = 35 years old, r = 0.9995, 09997, 0.9992, 0.9988, and 0.9999, respectively. CONCLUSION: The authors found that HbA1C (DCCT/NGSP) and HbA1C (IFCC) are not affected by sex but are influenced significantly by age group. Since HbA1C (IFCC) will be widely used in routine diabetes management, the authors recommend all laboratories provide the results of HbA1C in both DCCT/NGSP and IFCC methods during this interim period.

Annual laboratory checkup: early signs of health problems in young and middle-age adults.

The objective of this descriptive study was to review the usefulness and relevance of the present parameters provided in an annual laboratory health checkup program. Three hundred sixty-four volunteers were randomly selected, composed of 141 males and 223 females age 15 to 81 years old. Samples from all the volunteers were analyzed for CBC, FBG, BUN, Cr, uric acid, Chol, HDLc, Tg, AST, ALT, ALP, UA and stool examination. More than half the young adults (67.7%, 63 of 93) had abnormal laboratory results. This was higher than in the middle-age group (56.8%, 154 of 271).