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 difference
PT sec 10.0 – 11.8 <0.005 0.003* 
APTT sec 24.7 – 31.7 0.006 0.232 
TCT sec 13.8 – 17.4 0.035 0.198 
Fib g/L Clauss 1.6 – 4.2 0.190 t-test not significant 
Fib g/L Derived 2.1 – 4.9 0.200 t-test not significant 
II % 82 – 133 <0.005 0.019* 
V% 70 – 150 0.021 0.303 
VII % 60 – 164 0.008 0.037* 
X% 75 – 147 0.539 t-test not significant 
VIII % 48 – 204 <0.005 0.520 
IX % 65 – 142 <0.005 0.275 
XI % 61 – 142 <0.005 0.394 
XII % 59 – 133 0.088 t-test not significant 
Protein C % 75 – 160 0.036 0.024* 
ATIII % 86 – 128 0.329 t-test not significant 
ParameterReference RangeAnderson Darling P-Value P-value for normal distributionMann Whitney U-test (M versus F) *=significant difference
PT sec 10.0 – 11.8 <0.005 0.003* 
APTT sec 24.7 – 31.7 0.006 0.232 
TCT sec 13.8 – 17.4 0.035 0.198 
Fib g/L Clauss 1.6 – 4.2 0.190 t-test not significant 
Fib g/L Derived 2.1 – 4.9 0.200 t-test not significant 
II % 82 – 133 <0.005 0.019* 
V% 70 – 150 0.021 0.303 
VII % 60 – 164 0.008 0.037* 
X% 75 – 147 0.539 t-test not significant 
VIII % 48 – 204 <0.005 0.520 
IX % 65 – 142 <0.005 0.275 
XI % 61 – 142 <0.005 0.394 
XII % 59 – 133 0.088 t-test not significant 
Protein C % 75 – 160 0.036 0.024* 
ATIII % 86 – 128 0.329 t-test not significant 
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Kruskal 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.

Topics:
activated partial thromboplastin time measurement, antithrombin iii, blood coagulation, blood coagulation factors, blood type o, calibration, coagulation process, protein c, reference values, actins

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Corresponding author

2005, The American Society of Hematology
2005
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