New Coagulation Assays Reference Ranges for Healthy Adults Using the Modern Sysmex CA-1500 Coagulometer.

Abstract

Reference ranges (RRs) in coagulation are applicable only to specific analyser and reagent combinations and frequently need to be re-established if any of these are changed. In no other sphere of clinical laboratory practice are RRs more affected by such a wide range of multiple demographic and pre-analytical variables. For most routine clinical laboratories therefore, the collection of multiple, separate RRs is not feasible so a representative group of healthy adults such as laboratory staff frequently constitute the reference population from which these limits are calculated. Early morning venous samples were collected into glass B-D Vacutainers (Ref: 367691) from 221 healthy laboratory personnel (F= 159; M = 62) aged 20–63 yrs for both gender. Age groups were equally represented. Samples were processed on a Sysmex CA-1500 analyser within 1 hour of collection. Appropriate NCCLS guidelines were followed throughout. Reagents employed were - Actin FSL (APTT); Innovin (PT); Dade-Behring reference, calibration and deficient plasmas (factor assays); Dade-Behring kit ref: OWWR15 (ATIII); Chromogenix kit ref: 82209863 (Protein C). Outliers were excluded, data examined for normal distribution from histograms and significance levels calculated from the Anderson - Darling test of normality. RRs for normally distributed parameters were calculated using means ± 2SDs. RRs for non-normally distributed parameters were calculated using the log natural transformation and the antilog of 2.5- and 97.5- percentiles. Italicised parameters shown below are non-normally distributed.ParameterReference RangeAnderson Darling P-Value P-value for normal distributionMann Whitney U-test (M versus F) *=significant differencePT sec10.0 – 11.8<0.0050.003*APTT sec24.7 – 31.70.0060.232TCT sec13.8 – 17.40.0350.198Fib g/L Clauss1.6 – 4.20.190t-test not significantFib g/L Derived2.1 – 4.90.200t-test not significantII %82 – 133<0.0050.019*V%70 – 1500.0210.303VII %60 – 1640.0080.037*X%75 – 1470.539t-test not significantVIII %48 – 204<0.0050.520IX %65 – 142<0.0050.275XI %61 – 142<0.0050.394XII %59 – 1330.088t-test not significantProtein C %75 – 1600.0360.024*ATIII %86 – 1280.329t-test not significantKruskal Wallis tests on our data indicate that all coagulation factors are positively associated with age except factors IX and XII. Significant differences (p=0.014) in factor VIIIc was found between those of blood group O and non group O. Significant correlation was found between declining APTTs and associated increasing factor VIIIc when measured in individual volunteers.