Skip to main content

Table 1 Summary of findings

From: Systematic review and meta-analysis: rapid diagnostic tests versus placental histology, microscopy and PCR for malaria in pregnant women

What is the diagnostic accuracy of microscopy of peripheral and placental blood to correctly identify histologically confirmed placental malaria (PM)?
Population Pregnant women
Settings At delivery where both placental and peripheral material is available; mostly P. falciparum infections
Index test Microscopic examination of placental or peripheral blood slide
Reference Test Histological examination of placental biopsies
Type of test Effect
[95% CI]
Participants
(studies)
Median prevalence
(range)
Implications of results Quality and comments
Microscopy of placental blood Sensitivity 54%
[40-67]
Specificity 97%
[95-98]
2153
(5)
24.4%
(18.4-35.5)
With a prevalence of 25%, 25 out of 100 pregnant women will develop PM; 12 and 14 patients will be missed by placental and peripheral microscopy. Representative patient spectrum; uncertain if all tests blinded; withdrawals poorly Reported.
Microscopy of peripheral blood Sensitivity 44%
[34-54]
Specificity 92%
[86-95]
4044
(8)
28.6%
(17.2-52.5)
With a prevalence of 25%, 6 patients will be false positive in peripheral microscopy, but treatment is not harmful and can act as prophylaxis during the rest of the pregnancy. Representative patient spectrum; uncertain if all tests blinded; withdrawals poorly reported; 1 study did not report selection criteri; 1 did not report the execution of the reference test; risk of verification bias in study.
What is the diagnostic accuracy of RDTs and PCR to correctly identify PM confirmed by microscopy of placental blood?
Population Pregnant women
Settings At delivery where both placental- and peripheral blood is available; mostly P. falciparum infections
Index test RDT or PCR with peripheral or placental blood
Reference Test Microscopic examination of placental blood slide
Type of test/subgroups Effect
[95% CI]
Participants
(studies)
Median
prevalence
(range)
Implications of results Quality and comments
Microscopy of peripheral blood Sensitivity
72%
[62-80]
Specificity
98%
[95-99]
16609
(26)
15.9%
(3.3-74.0)
Of 16 of 100 patients positive in placental blood, 4 would be missed in peripheral blood by microscopy. Representative patient spectrum; 4 did not describe selection criteria; execution of index/reference test not reported in 13 tests
RDT of placental and peripheral blood
Peripheral and placental blood pooled together Sensitivity
81%
[62-92]
Specificity
94%
[76-99]
3141
(5)
16.2%
(2.4-11 34.9)
Of 16 of 100 patients positive with placental blood microscopy, 3 would be missed in any type RDT. Of 11 of 100 patients positive with placental blood microscopy, 3 patients would be missed by RDTs with placental blood. With a prevalence of 16%, 5 patients will be false positive with RDTs compared to placental blood microscopy. Representative patient spectrum; uncertain if all tests blinded; withdrawals and uninterpretable results poorly reported; execution of test not reported in 3/7 tests; 1 study did not report selection criteria.
only placental Blood Sensitivity
76%
[44-92]
Specificity
95%
[87-99]
2124
(4)
11.20%
(2.4 -22.6)
  
PCR of placental and peripheral blood
all types of PCR Sensitivity
86%
[65-95]
Specificity
77%
[71-82]
2608
(6)
18.5%
(1.7-34.9)
Of 18 of 100 patients that test positive in placental blood microscopy, 3 would be missed by PCR, but 19 would be false positive. Representative patient spectrum; uncertain if all tests blinded; withdrawals and uninterpretable results poorly reported.
What is the diagnostic accuracy of RDTs and PCR to correctly identify microscopically confirmed peripheral malaria infection during pregnancy?
Population Pregnant women
Settings During pregnancy, placental examination not possible; mostly P. falciparum infections
Index test RDT or PCR with peripheral blood
Reference Test microscopic examination of peripheral blood slide
Type of test/subgroups Effect [95% CI] Participants (studies) Median
prevalence
(range)
Implications of results Quality and comments
RDT of peripheral blood
all types (pLDH and HRP2) Sensitivity 81%
[55-93]
Specificity 94%
[82-98]
5340
(7)
17.60%
(1.3-51.3)
Of 18 of 100 patients positive in peripheral blood microscopy, 3 would be missed in any type RDT. Of 28 of 100 patients positive in peripheral blood microscopy, 2 patients would be missed in HRP2 RDTs. Representative patient spectrum; uncertain if all tests blinded; withdrawals and uninterpretable results poorly reported; test execution not reported in 3/7 tests; 1 study did not report selection criteria.
only HRP2 based Sensitivity
94%
[91-96]
Specificity 81%
[71-88]
1834(4) 28.10%
(17.6-51.3)
With a prevalence of 28%, 14 patients will be false positive with HRP2 RDTs compared to peripheral blood microscopy.  
PCR of peripheral blood
all types of PCR Sensitivity 94%
[86-84]
5741
(11)
19.0%
(5.3-51.3)
Of 19 of 100 patients that test positive in peripheral blood microscopy, only 1 would be missed by PCR, but 20 would be false positive compared to peripheral blood microscopy. Representative patient spectrum; uncertain if all tests blinded; withdrawals and uninterpretable results poorly reported;