Determination of the length of sedimentation reaction in blood using the TEST 1 system: comparison with the Sedimatic 100 method, turbidimetric fibrinogen levels, and the influence of M-proteins.

BACKGROUND: Determination of the length of sedimentation reaction in blood (LSRB) is frequently used in daily practice to assess disease intensity. Recently, a micro-sedimentation method was introduced (TEST 1) that uses EDTA anti-coagulated blood samples. The aim of this study was to characterize this method by comparing it to a conventional Westergren method (Sedimatic 100). Furthermore, correlation between fibrinogen and the LSRB and the influence of M-proteins on the LSRB was investigated. METHODS: Unselected paired samples were used for comparison between the TEST 1 and Sedimatic 100 methods (n=733); fibrinogen was measured in EDTA samples (n=765) using a turbidimetric method. Furthermore, LSRB was measured in 29 EDTA samples in paired serum tubes from patients in whom an M-protein was detected. RESULTS: TEST 1 showed excellent correlation with the Sedimatic 100 method (y=1.00x; n=733; r=0.92, 95% CI 0.90-0.93; p<0.0001), and had no significant bias (0.15 mm/h, 95% CI -0.48 to 0.75 mm/h). Furthermore, TEST 1 LSRB showed satisfactory correlation with the fibrinogen content (y=3.13+0.06x; n=765; r=0.78, 95% CI 0.75-0.80; p<0.0001). In samples containing M-proteins, satisfactory correlation between the M-protein content and TEST 1 LSRB was found (y=0.69+0.22x; n=29; r=0.71, 95% CI 0.45-0.85; p<0.0001), while excellent correlation was found when only M-proteins of the IgM type were taken into account (y=-0.95+0.23x; n=9; r=0.93, 95% CI 0.71-0.99; p<0.0002). CONCLUSIONS: The results confirm previous reports that TEST 1 is a reliable method to measure the LSRB, and shows for the first time the quantitative relationship between TEST 1 LSRB and M-proteins, particularly those of the IgM type.

Folic acid status of paediatric patients with sickle cell disease

We investigated whether paediatric patients with sickle cell disease (9ñ4 years; 27 HbSS; 19 HbSC) have different folic acid status compared with age-, sex-and race-matched HbAA controls (n=20), and whether their folic acid status can be improved by folic acid supplementation. The patients were supplemented with vitamins B6 and B12 during one week and with folic acid during the next week. Circulating folic acid, homocysteine, vitamin B6 and vitamin B12 levels were measured at baseline (patients and controls), after 1 and 2 weeks (patients). The patients had similar folic acid, vitamin B6 and vitamin B12, but higher homocysteine levels, compared with HbAA controls (12.7ñ4.5 vs 10.9ñ3.5 mmol/l;p=0.04). Vitamin B6 and B12 supplementation did not change their homocysteine levels, but folic acid supplementation caused a 52 percent reduction (to 5.7ñ1.6). We conclude that patients with sickle cell disease have adequate vitamin B6 and B12 status, but suboptimal folic acid status. They may benefit from folic acid supplementation to reduce their high risk for endothelial damage.(AU)

Screening of cord blood for haemoglobinopathies and thalassaemia by high-performance liquid chromatography - abstract

A high-performance liquid chromatography (HPLC) method for the screening of haemoglobins in cord blood was evaluated and the gene frequencies of the structural haemoglobin variants HbS and HbC and the synthesis variants O- and á+ -thalassaemia were studied in babies born on the Caribbean island of Curacao, the Netherlands Antilles. In 3 months, 67.2 percent of all (748) newborns were screened and 122 (24.3 percent) had an abnormal haemoglobin pattern, of which 53 (43.4 percent) had a haemoglobinopathy (HbS or HbC), 64(52.2 percent) O-thalassaemia (Hb Barts > 0.5 percent, corresponding with heterozygous or homozygous O-thalassaemia-2) and 5 (4.1 percent) a haemoglobinopathy plus O-thalassaemia. None of the newborns with heterozygous HbS and HbC had concomitant á+-thalassaemia. The population genotype frequency of heterozygous O-thalassaemia -2 remain undetected. The data are in excellent agreement with comparable published results. The HPLC method proved pre-eminently suitable for the screening of cord blood samples. (AU)