BurmaCambodia-8

Laboratory, Office and Home Pregnancy Tests

As dealt with, in previous reports, hCG is a mixture of biologically active variants and multiple degradation products, pregnancy blood or serum and urine may contain as many as 11 different different variants of hCG. Here we examine hCG laboratory, clinical office (Point-Of-Care) and home (Over-The-Counter test) pregnancy tests, and how well they detect hCG and do or do not detect hCG variants.

We start off by examining laboratory tests –

Table 1. Specificity of automated laboratory total hCG tests (see Cole LA, DuToits S, Higgins TN. Total hCG tests.

ClinChem Acta, 2011;412:2216-2222.). Results are percentage values, this is nmol/L as determined in the assay as a

percentage of the absolute concentration of tested standard. ßCTP is ß-subunit C-terminal peptide.

Abbott Architect Abbott AxSYM Beckman Access 2 Beckman DxI 800 Ortho Vitros ECiQ Roche Elecsys hCG+ß Siemens Centaur Siemens Dimension Siemens Immulite Tosoh A1A
   Serum standards
   hCG 96% 103% 103% 100% 112% 109% 104% 96% 96% 95%
   Hyperglycosylated hCG 86% 85% 120% 98% 68% 78% 81% 67% 105% nd
   Nicked hCG 70% 99% 84% 71% 80% 69% 66% 65% 115% nd
   Nicked hCG missing CTP 0% 0% 0% 0% 0% 12% 0% 10% 109% 16%
   Nicked hyperglycosylated
hCG
40% 46% 46% 51% 80% 100% 40% 80% 103% 70%
   Asialo (no sialic acid) hCG 35% 69% 48% 46% 85% 46% 39% 65% 114% 59%
   hCGß 87% 94% 142% 136% 47% 102% 47% 47% 111% 66%
   Nicked hCGß 33% 51% 56% 63% 19% 53% 19% 41% 107% 60%
   ß-core fragment 1% 1% 1% 1% 1% 16% 1% 1% 35% 1%

 

As shown in Table 1, laboratory hCG tests invariably detect hyperglycosylated (68%-120% efficiency), invariably detect nicked hCG (65%-115%), and invariably detect asialo hCG (35%-114%) and hCG free ß-subunit (47%-136%). The worst problem is that 9 of the 10 automated laboratory tests do not detect molecule missing the C-terminal peptide (CTP). Only one assay detects all variants reasonably equally, the Siemens Immulite assay.

All assay are designed for testing serum samples, although can be used for testing urine samples. All have a sensitivity of between 0.5 and 2 mIU/ml.

Multiple quick dip and machine read quick tests are designed for clinic uses, these are call Point-Of-Care or POC tests. These are designed to give results in 5 minutes or less.

Table 2. Sensitivity of POC pregnancy tests to detect hCG, hyperglycosylated hCG and hCG free ß-subunit.

Device hCGin mIU/ml Hyperglycosylated hCGmolar mIU/ml equivalents Free ß-subunit in molarmIU/mL equivalents
Quidel QuickVue One-Step 24 24 88
Beckman Coulter Icon 25 12 12 88
Siemens Clinitest Digital Analyzer 50 100 >500
Inverness Acceava hCG Basic II 18 50 >500
Mainline Maxie hCG 24 50 >500

 

As shown in Table 2, these assay have sensitivity between 12 and 24 mIU/ml. As such, they will not detect pregnancy until approximately the day of missing the menstrual period. These were each tested with 30 urine samples on that day. The most sensitive test, of Beckman Coulter Icon test detected 77% of pregnancies, the Quidel Quick-Vue and Inverness Acceava test detected 67% of pregnancies, the Mainline Maxie detected 50%, and the Siemens Clinitest 43% od pregnancies. It must be remembered that hyperglycosylated hCG is the principal hCG form present in serum and urine in the earliest weeks of pregnancy. Only the Quidel Quick-Vue and the Beckman Coulter Icon equally detected hCG and hyperglycosylated. This is a major detriment to the other tests.

Home pregnancy tests, called over-the-counter (OTC) hCG tests is another issue. Six tests lead the world market, First Response, First Response Gold Digital, EPT and EPT Certainty Digital. ClearBlue Easy and ClearBlue Easy Digital. No other home pregnancy test or OTC tests can be compared to these 6 top tests. While the manual tests require care reading according to manufacturers instructions, commonly the appearance or non-appearance of a line or cross in the result window. The digital test have the simplicity of displaying whether you are pregnant or not.

As shown in Table 3, home or OTC tests can detect or mostly detect hyperglycosylated hCG,

Table 3. Evaluation of over-the-counter tests with urine mixtures containing pure hCG, pure free ß-subunit and pure hyperglycosylated hCG standards. Concentration of standards are molar equivalents of hCG in mIU/ml.

Concentration  First ResponseManual

 

First ResponseGold Digital

 

 

EPT Manual 

 

EPT CertaintyDigital

 

 

ClearBlueEasy Manual

 

 

ClearBlueEasy Digital

 

Trial 1. Non-pregnant female urine containing hCG dimer 1st RR standard
Sensitivity 3.3 5.5 11 11 11 11
Trial 2. Non-pregnant female urine containing C5 hyperglycosylated hCG standard
Sensitivity 3.3 5.5 11 22 11 22
Trial 3. Non-pregnant female urine containing free ß-subunit 1st RR standard
Sensitivity 9.0 9.0 >90 >90 >90 >90

but poorly detect or do not detect hCG free ß-subunit, The sensitivity of these test are 3.3 mIU/ml for First Response manual, 5.5 mIU/ml for Fist Response Gold Digital, 11 mIU/ml for EPT Manual, 11 mIU/ml for EPT Certainty Digital (disputed because poorly detects hyperglycosylated hCG), 11 mIU/ml for ClearBlue Easy Manual and 11 mIU/ml for Clear Blue Easy Digital (disputed because poorly detects hyperglycosylated hCG).

We examined how well these 6 tests detected 80 pregnant women’s daily urines over 11 days, or 880 urines tested (Table 4).

Table 4. Evaluation of over-the-counter tests with 880 urines from 80 women achieving pregnancy.

         Day relative to missed period  Achieved
Pregnancy atthis time
hCG median
concentrationmIU/ml
First Response

Manual

First ResponseGold Digital EPT

Manual

 

EPT
Digital
ClearBlue

Easy Manual

ClearBlue
Easy Digital
Tri
Pregnant woman, 80 total
-6 days 29% 2.1 25% 25% 0% 0% 0% 0%
-5 days 40% 2.9 33% 25% 5.0% 5.0% 5.0% 5.0%
-4 days 76% 5.2 58% 42% 6.3% 6.3% 8.8% 3.8%
-3 days 88% 12 74% 68% 14% 18% 27% 12%
-2 days 92% 21 76% 81% 29% 31% 29% 28%
-1 days 99% 40 93% 91% 42% 55% 57% 51%
Day of missing period 99% 70 96% 96% 53% 68% 67% 51%
+1 days 100% 143 100% 96% 64% 71% 74% 69%
+2 days 100% 227 100% 99% 77% 79% 81% 77%
+3 days 100% 302 100% 100% 80% 86% 87% 84%
+4 days 100% 534 100% 100% 100% 100%

 

Clearly, from the test with 880 separate urine, the most comprehensisve test of home/OTC test ever performed (see home page G. Dr. Cole’s Pertinent Publications), the tests which can detect pregnancy the earliest are First Response Manual and then First Response Gold Digital. From Table 4, EPT and ClearBlue Easy cannot detect 100% of pregnancies until 4 days after missing the menstrual period. This study was performed partially blind (all urines coded and devices blinded to the extent possible).